Adobe Acrobat Capture

November 17, 2023 by Thor 1 Comment

During the recent PRONOM Research Week, I noticed a file format with no description and no signature.

All I had to go on was it was an Adobe format and the acronym “ACD”. One of the first results that came up in a google search was a post in the Adobe forums with someone asking what to do with some old ACD and ACI files they found on a disc, circa 2000, labeled “Adobe Capture”. The only thing I remember about Adobe Capture was some scanning tools related to Adobe Acrobat, but I didn’t remember coming across any ACD files related to Acrobat.

Initially it wasn’t easy to find more information on this format. Eventually I was able to narrow it down to stand-alone software adobe released called “Adobe Acrobat Capture”. Originally released in 1995 it was eventually discontinued in 2010. The software was marketed under the ePaper name and connected to Acrobat through the creation of a PDF from scanned images. The software was compatible with many scanner models and would process the scanned images, run Optical Character recognition, and export to a searchable PDF. These tools are built into Adobe Acrobat today.

One of the reasons the software was being so elusive is the fact it was sold with a high price tag and required the use of a hardware key, or dongle, in order to process scans. The hardware key also managed the type of license you purchased which may limit the number of pages you are allowed to scan within a certain period of time. So the software is very difficult to run today, if you do happen to find a copy out there in Internet land.

In order to document these file formats for preservation purposes I needed to find some samples. I was excited to find a demonstration CD on the Internet Archive, but unfortunately it contained no examples of the ACD file format.

A little sleuthing on the Wayback Machine helped me find a few user guides and brochures. I was also able to find there was three versions of Adobe Acrobat Capture. In a Product Brochure, you can see a screenshot of the software with a document open with the ACD extension.

If you are OCD like me you might have noticed the window in this screenshot is typical of the older Windows 3.1 or Windows NT system. So this was indeed an older product released by Adobe.

The Adobe Acrobat Capture 3.0 Demonstration CD-ROM from the Internet Archive luckily has a UserGuide PDF on the disc and was able to help me understand the ACD format a little more.

Looks like the ACD format is an intermediate format used by the software to manage the process between scanning and export to PDF. ACD was also defined as an “Acrobat Capture Document” which makes sense. They were also mentioned as being “multipage files in Acrobat Capture Document (ACD)”. The UserGuide also mentioned an ACP format which it referenced as “one-page files are in Acrobat Capture Page (ACP) format.” So more research is needed.

Lets start with Adobe Acrobat Capture 2.0 as I managed to get a few samples from an installer I found. Here is a hexdump of an ACD file and its corresponding ACI file.

hexdump -C CONTRACT.ACD | head
00000000  02 04 47 47 c9 00 86 b5  01 00 b6 27 02 00 01 00  |..GG.......'....|
00000010  f5 00 5e 00 3b 96 02 00  01 6e 63 6a 00 00 88 68  |..^.;....ncj...h|
00000020  00 00 26 00 44 3a 5c 43  4f 44 45 5c 47 47 5c 50  |..&.D:\CODE\GG\P|
00000030  52 4f 44 55 43 54 2e 33  32 53 5c 49 4e 5c 63 6f  |RODUCT.32S\IN\co|
00000040  6e 74 72 61 63 74 2e 61  63 69 00 00 00 00 00 00  |ntract.aci......|
00000050  7c 33 c0 27 00 40 ff ff  ff 00 03 00 03 00 00 00  ||3.'.@..........|
00000060  00 00 00 00 00 00 40 00  00 00 00 00 00 03 00 00  |......@.........|
00000070  00 00 00 00 00 00 00 40  00 00 00 00 09 00 0a ab  |.......@........|
00000080  04 0b 14 b5 04 39 19 00  40 00 00 00 00 0c 14 b0  |.....9..@.......|
00000090  04 38 19 b0 04 08 00 0a  7f 06 d3 11 89 06 39 17  |.8............9.|

hexdump -C CONTRACT.ACI | head
00000000  49 49 2a 00 b3 0c 02 00  35 80 78 a0 80 35 c0 78  |II*.....5.x..5.x|
00000010  a4 80 35 40 3c 54 40 01  e2 b2 01 e2 b2 01 e2 b2  |..5@<T@.........|
00000020  01 e2 b2 01 e2 b2 01 e2  b2 01 e2 b2 01 e2 b2 01  |................|
00000030  e2 b2 01 e2 b2 01 e2 b2  01 e2 b2 01 e2 b2 01 e2  |................|
00000040  b2 01 e2 b2 01 e2 b2 01  e2 b2 01 e2 b2 01 e2 b2  |................|
00000050  01 e2 b2 01 e2 b2 01 e2  b2 01 e2 b2 01 e2 b2 01  |................|
00000060  e2 b2 01 e2 b2 01 e2 b2  01 e2 b2 01 e2 b2 01 e2  |................|
00000070  b2 01 e2 b2 01 e2 b2 01  e2 b2 01 e2 b2 01 e2 b2  |................|
00000080  01 e2 b2 01 e0 b0 01 e0  b0 01 e0 b0 01 e0 b0 01  |................|
00000090  e0 b0 01 e0 b0 01 e0 b0  01 e0 b0 01 e0 b0 01 e0  |................|

The ACD file is unique, PRONOM and even TrID was unaware of the format. But to the keen observer, the ACI format is very recognizable. You may have seen this header before:

Lets take a closer look at an ACI file to see if they are a true TIFF image or if there is any customization to the format.

tiffinfo CONTRACT.ACI 
=== TIFF directory 0 ===
TIFF Directory at offset 0x20cb3 (134323)
  Subfile Type: (0 = 0x0)
  Image Width: 2544 Image Length: 3295
  Resolution: 300, 300
  Bits/Sample: 1
  Compression Scheme: CCITT RLE
  Photometric Interpretation: min-is-white
  Samples/Pixel: 1
  Rows/Strip: 32
  Planar Configuration: single image plane
  Software: HALO Desktop Imager

exiftool -D CONTRACT.ACI 
    - ExifTool Version Number         : 12.60
    - File Name                       : CONTRACT.ACI
    - Directory                       : TUTORIAL/SAMPOUT
    - File Size                       : 134 kB
    - File Modification Date/Time     : 1995:07:10 16:02:08-06:00
    - File Access Date/Time           : 2023:11:14 15:41:02-07:00
    - File Inode Change Date/Time     : 2023:11:08 08:34:18-07:00
    - File Permissions                : -rwxrwxrwx
    - File Type                       : TIFF
    - File Type Extension             : tif
    - MIME Type                       : image/tiff
    - Exif Byte Order                 : Little-endian (Intel, II)
  254 Subfile Type                    : Full-resolution image
  256 Image Width                     : 2544
  257 Image Height                    : 3295
  258 Bits Per Sample                 : 1
  259 Compression                     : CCITT 1D
  262 Photometric Interpretation      : WhiteIsZero
  273 Strip Offsets                   : (Binary data 625 bytes, use -b option to extract)
  277 Samples Per Pixel               : 1
  278 Rows Per Strip                  : 32
  279 Strip Byte Counts               : (Binary data 448 bytes, use -b option to extract)
  282 X Resolution                    : 300
  283 Y Resolution                    : 300
  305 Software                        : HALO Desktop Imager
    - Image Size                      : 2544x3295
    - Megapixels                      : 8.4

Looks like a true TIFF image with no special tags or unique properties. They are 1-bit TIFF’s compressed with CCITT RLE. Not sure there would be any need to create a special signature for these ACI files.

Looking closer at the ACD file format, we can see they reference ACI files, so probably safe to assume the ACD file doesn’t contain the full raster data for each image:

hexdump -C Report.acd
00000000  02 04 47 47 c9 00 9a 8b  00 00 d4 ce 00 00 03 00  |..GG............|
00000010  f5 02 5f 00 00 61 01 00  01 6e 63 6a 01 00 30 5f  |.._..a...ncj..0_|
00000020  00 00 27 00 63 3a 5c 63  61 70 74 75 72 65 32 5c  |..'.c:\capture2\|
00000030  73 61 6d 70 6c 65 73 5c  6f 75 74 5c 52 65 70 6f  |samples\out\Repo|
00000040  72 74 5f 30 30 30 31 2e  61 63 69 00 00 01 00 00  |rt_0001.aci.....|
00000050  00 00 00 00 00 00 00 00  00 00 e8 03 00 00 01 00  |................|
00000060  01 00 00 00 00 00 00 00  00 00 08 00 52 65 70 6f  |............Repo|
00000070  72 74 30 31 00 00 00 00  70 33 d8 27 00 40 ff ff  |rt01....p3.'.@..|
*
00005f40  07 00 40 6f 00 09 00 40  01 6e 63 6a 02 00 52 2c  |..@o...@.ncj..R,|
00005f50  00 00 27 00 63 3a 5c 63  61 70 74 75 72 65 32 5c  |..'.c:\capture2\|
00005f60  73 61 6d 70 6c 65 73 5c  6f 75 74 5c 52 65 70 6f  |samples\out\Repo|
00005f70  72 74 5f 30 30 30 32 2e  61 63 69 00 00 00 00 00  |rt_0002.aci.....|
00005f80  00 00 00 00 4e 0c fe ff  ff ff e8 03 00 00 01 00  |....N...........|
00005f90  01 00 00 00 00 00 00 00  00 00 08 00 52 65 70 6f  |............Repo|
00005fa0  72 74 30 32 00 00 00 00  4c 31 f0 27 00 40 ff ff  |rt02....L1.'.@..|

From the limited sample set I have access, all the ACD files begin with the same Hex values, “02044747C900”. Along with the common header we can assume there should be at least one ACI file referenced in the first part of the file. Because it is referenced as a filepath, the ACI string would be variable in its offset.

Adobe Acrobat Capture 3.0 turns out to be a different format. But looks familiar………

hexdump -C Contract.acd | head
00000000  50 4b 03 04 14 00 00 00  08 00 3b ba 6e 57 23 9d  |PK........;.nW#.|
00000010  8e b8 3d 00 00 00 3e 00  00 00 09 00 40 00 46 49  |..=...>.....@.FI|
00000020  4c 45 53 2e 4c 53 54 0a  00 20 00 00 00 00 00 00  |LES.LST.. ......|
00000030  00 00 00 80 e6 e9 ca 50  17 da 01 80 e6 e9 ca 50  |.......P.......P|
00000040  17 da 01 80 e6 e9 ca 50  17 da 01 4e 55 18 00 4e  |.......P...NU..N|
00000050  55 43 58 09 00 46 00 49  00 4c 00 45 00 53 00 2e  |UCX..F.I.L.E.S..|
00000060  00 4c 00 53 00 54 00 8b  76 74 76 31 8c e5 e5 f2  |.L.S.T..vtv1....|
00000070  0c 76 f6 f7 0d f0 0f f6  0c 71 b5 0d 09 0a 75 e5  |.v.......q....u.|
00000080  e5 f2 0b f5 75 f3 f4 71  0d b6 35 e4 e5 02 31 fc  |....u..q..5...1.|
00000090  1c 7d 5d 0d 6d 9d f3 f3  4a 8a 12 93 4b f4 12 93  |.}].m...J...K...|

sf Contract.acd 
---
siegfried   : 1.10.1
scandate    : 2023-11-15T09:10:01-07:00
signature   : default.sig
created     : 2023-10-11T15:10:17-06:00
identifiers : 
  - name    : 'pronom'
    details : 'DROID_SignatureFile_V114.xml; container-signature-20230822.xml'
---
filename : 'Contract.acd'
filesize : 79002
modified : 2023-11-14T23:17:53-07:00
errors   : 
matches  :
  - ns      : 'pronom'
    id      : 'x-fmt/263'
    format  : 'ZIP Format'
    version : 
    mime    : 'application/zip'
    basis   : 'byte match at [[0 4] [78886 3] [78980 4]]'
    warning : 'extension mismatch'

Yep, its a zip container file. lets take a peek inside to see what it is composed of.

7z l Contract.acd 
--
Path = Contract.acd
Type = zip
Physical Size = 79002

   Date      Time    Attr         Size   Compressed  Name
------------------- ----- ------------ ------------  ------------------------
2023-11-14 23:17:54 ....A           62           61  FILES.LST
2023-11-14 23:17:54 ....A          410          226  Contract.acd
2023-11-14 23:17:52 ....A       150213        78093  Contract.acp
------------------- ----- ------------ ------------  ------------------------
2023-11-14 23:17:54             150685        78380  3 files

The the Contract ACD file is like a nesting doll, an ACD within an ACD. Lets see what the ACD and ACP is made of.

hexdump -C Contract.acd | head
00000000  00 01 00 00 00 02 04 47  47 2d 01 9a 01 00 00 02  |.......GG-......|
00000010  00 00 00 02 00 01 01 00  00 00 01 00 00 00 04 04  |................|
00000020  00 00 00 09 00 57 69 6e  67 64 69 6e 67 73 05 00  |.....Wingdings..|
00000030  41 72 69 61 6c 0b 00 43  6f 75 72 69 65 72 20 4e  |Arial..Courier N|
00000040  65 77 0f 00 54 69 6d 65  73 20 4e 65 77 20 52 6f  |ew..Times New Ro|
00000050  6d 61 6e 05 01 00 00 00  02 00 00 00 78 01 00 00  |man.........x...|
00000060  0f 00 54 69 6d 65 73 20  4e 65 77 20 52 6f 6d 61  |..Times New Roma|
00000070  6e 00 00 00 20 0b 00 00  c0 0a 00 00 00 00 00 00  |n... ...........|
00000080  00 06 00 00 00 0f 00 54  69 6d 65 73 20 4e 65 77  |.......Times New|
00000090  20 52 6f 6d 61 6e 00 00  00 20 0c 00 00 00 0c 00  | Roman... ......|

hexdump -C Contract.acp | head
00000000  25 50 44 46 2d 31 2e 33  0d 25 e2 e3 cf d3 0d 0a  |%PDF-1.3.%......|
00000010  31 20 30 20 6f 62 6a 0d  3c 3c 20 0d 2f 54 79 70  |1 0 obj.<< ./Typ|
00000020  65 20 2f 43 61 74 61 6c  6f 67 20 0d 2f 50 61 67  |e /Catalog ./Pag|
00000030  65 73 20 32 20 30 20 52  20 0d 2f 53 74 72 75 63  |es 2 0 R ./Struc|
00000040  74 54 72 65 65 52 6f 6f  74 20 34 20 30 20 52 20  |tTreeRoot 4 0 R |
00000050  0d 2f 43 41 50 54 5f 49  6e 66 6f 20 3c 3c 20 2f  |./CAPT_Info << /|
00000060  56 20 33 30 31 20 2f 46  53 20 5b 20 28 57 69 6e  |V 301 /FS [ (Win|
00000070  67 64 69 6e 67 73 29 28  41 72 69 61 6c 29 28 43  |gdings)(Arial)(C|
00000080  6f 75 72 69 65 72 20 4e  65 77 29 28 54 69 6d 65  |ourier New)(Time|
00000090  73 20 4e 65 77 20 52 6f  6d 61 6e 29 5d 20 2f 4c  |s New Roman)] /L|

The ACD has some of the same hex values as the previous version, but with some extra bytes at the beginning and it looks like the ACP is a straight up PDF. But may have some interesting tags, like “CAPT_info”.

The problem we will face when trying to write a signature for this version of ACD is the container signature needs a static file name to reference, and it appears the name of the container is also the name of the ACD file within the container. So every file will be different. I wish there was a way in the PRONOM signature syntax to reference an extension and ignore the filename, but currently there no method to do this. The only thing inside the container which seems to be consistent is the file “FILES.LST”. So lets take a peek inside if it.

hexdump -C FILES.LST | head
00000000  5b 41 43 44 31 5d 0d 0a  49 53 43 4f 4d 50 4f 53  |[ACD1]..ISCOMPOS|
00000010  49 54 45 3d 54 52 55 45  0d 0a 4e 55 4d 46 49 4c  |ITE=TRUE..NUMFIL|
00000020  45 53 3d 31 0d 0a 46 49  4c 45 4e 41 4d 45 31 3d  |ES=1..FILENAME1=|
00000030  43 6f 6e 74 72 61 63 74  2e 61 63 70 0d 0a        |Contract.acp..|

Ok, there seems to be some static information that is unique to the ACD format. I bet the string “[ACD1]” would be sufficient enough to make a solid signature.

This is a good format example of a limited amount of information on the file format used by a well known company which has become obsolete and disappeared. Take a look at my signatures, maybe you have some old ACD files you were unaware of!

Multiplan

November 10, 2023 by Thor Leave a comment

This is a follow up post to the post “EARLY MICROSOFT EXCEL” earlier this year.

I have to admit, often when I am researching file formats I can get distracted by a shinier format I come across. I often go down rabbit holes and forget the reason I started down the path I am on. I try and focus on the current needs in my life as a Digital Preservation Manager, but can get easily sidetracked. I always look forward to November every year so I can celebrate World Digital Preservation Day which sometimes comes along with a PRONOM research week. This gives me a chance to look at formats that may need attention which are not normally on my radar.

This week I a taking a look again at Multiplan. There is a PRONOM PUID for version 4, but does not have a description nor does it have a binary signature. It is was also lacking a File Format Wiki entry. So I decided to dive in. I had already bumped into the format while doing some research on early Microsoft Excel formats. This includes the SYLK format which needed a little update.

Microsoft Multiplan was the parent of Microsoft Excel. Multiplan was built for many different types of computers in the 1980’s, but was never ported to Windows. So to use Multiplan you have to be comfortable with using DOS. If you want to take Multiplan for a spin, head over to PCjs Machines and load up one of the many emulated systems they have.

In the end, Multiplan had four versions, but the last one, version 4.2, had some big changes, especially to the file format. More on that in a minute.

Mutiplan Version 1 – DOS

hexdump -C MP1.MOD  | head
00000000  08 e7 00 00 58 09 01 00  08 00 01 00 00 00 0a 00  |....X...........|
00000010  40 00 00 00 2e f5 0a 80  27 07 94 00 12 00 01 00  |@.......'.......|
00000020  0a 00 01 00 0c 0a 08 00  27 00 0d 80 04 00 01 00  |........'.......|
00000030  54 00 00 00 27 00 10 00  54 52 41 4e 53 46 48 f5  |T...'...TRANSFH.|
00000040  00 80 84 0a 68 61 52 f5  58 f5 5a f5 4e f5 0c 0a  |....haR.X.Z.N...|
00000050  12 00 01 00 72 f5 72 f5  0a 80 4b 0b 0f 00 12 00  |....r.r...K.....|
00000060  0c 0a 01 00 0c 00 01 00  08 00 20 4e 40 00 09 00  |.......... N@...|
00000070  8a f5 0a 80 4a 07 30 00  48 00 01 00 20 4e 00 00  |....J.0.H... N..|
00000080  28 0c 18 00 04 00 0d 80  03 00 28 0c 04 00 00 00  |(.........(.....|
00000090  26 00 00 00 54 52 d0 01  00 00 a4 f5 0a 00 62 0b  |&...TR........b.|

Mutiplan Version 1 – Macintosh

hexdump -C Multiplan1  | head
00000000  11 ab 00 00 13 e8 00 00  00 00 00 00 00 02 02 8c  |................|
00000010  00 18 00 0e 02 a4 02 b2  00 0e 02 fe 00 03 00 0e  |................|
00000020  00 bd 01 e3 2f 0f 00 08  15 5e 19 d1 03 5e 19 dd  |..../....^...^..|
00000030  61 60 60 5e 16 90 00 67  60 60 60 8f 5f 03 e8 7a  |a``^...g```._..z|
00000040  30 61 60 60 13 5f 03 e8  7b 90 00 67 60 60 60 8f  |0a``._..{..g```.|
00000050  16 85 67 60 60 60 8f 16  6d 85 61 60 60 13 5e 10  |..g```..m.a``.^.|
00000060  7b 90 00 67 60 60 60 8f  13 7a 31 14 6a d7 16 6e  |{..g```..z1.j..n|
00000070  85 14 77 60 16 6f 85 67  60 60 60 90 00 67 60 60  |..w`.o.g```..g``|
00000080  60 90 00 67 60 60 60 8f  13 7a 31 14 6a d7 16 70  |`..g```..z1.j..p|
00000090  85 14 77 60 16 71 85 67  60 60 60 90 00 67 60 60  |..w`.q.g```..g``|

Mutiplan Version 2 – DOS

hexdump -C MP2.MOD | head
00000000  0c ec 00 00 08 ab 08 00  1f 00 1a 00 03 00 27 03  |..............'.|
00000010  4b 05 00 00 00 00 00 00  00 00 00 1d c8 14 03 00  |K...............|
00000020  00 00 2f 00 9a 2e b3 fc  46 02 34 04 f3 16 00 00  |../.....F.4.....|
00000030  00 00 00 00 08 00 10 22  00 00 0d 06 84 1d 08 1d  |......."........|
00000040  ff 03 83 0a c8 18 48 1a  02 19 00 00 00 00 15 1b  |......H.........|
00000050  98 15 85 15 03 00 2a 00  00 37 46 32 1c 00 18 00  |......*..7F2....|
00000060  00 00 01 00 01 00 a9 03  0f 80 e8 14 00 00 01 00  |................|
00000070  6a 1c 00 00 01 00 0d 00  0f 80 0a 15 00 00 77 20  |j.............w |
00000080  00 00 01 00 6e 61 6c 20  00 00 2a 00 00 00 04 00  |....nal ..*.....|
00000090  00 00 0d 00 14 19 00 00  d4 06 0e 80 24 15 00 00  |............$...|

The DOS files for Version 2 begin with 0CEC0000 08AB0800, but a file for the Xenix system starts with 0AEC0000 08AB0800. So it appears the first byte may be different depending on the system.

hexdump -C MP3.MOD | head                         
00000000  0c ed 00 00 08 ab 08 00  1f 00 1a 00 00 00 00 00  |................|
00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00000110  00 00 02 00 01 00 00 00  00 00 ff 0f ff 00 00 00  |................|
00000120  00 00 05 00 06 00 46 00  36 00 42 00 00 00 00 00  |......F.6.B.....|
00000130  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000140  00 00 00 00 00 00 00 00  00 00 00 00 00 01 00 00  |................|
00000150  00 fe 0f 00 fe 00 00 00  00 00 00 00 00 00 00 00  |................|
00000160  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

The DOS files for Version 3 begin with a similar hex pattern, 0CED0000 08AB0800. This would make sense as the documentation for Multiplan 4.2 states it supports opening of Version 2 & 3, but not Version 1.

There was also a companion product that went along with Multiplan, it was called Microsoft Chart. Here is a file from version 3:

hexdump -C EXAMPLE1.MC | head
00000000  90 01 00 00 08 ab 00 00  00 00 00 00 00 00 04 00  |................|
00000010  80 00 05 00 04 00 43 10  00 00 00 00 00 00 00 00  |......C.........|
00000020  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00000080  e8 ff 04 00 00 22 24 36  a4 1f 00 00 11 00 24 00  |....."$6......$.|
00000090  03 00 64 00 00 00 cc 0c  cc 0c cc 0c cc 0c 00 00  |..d.............|
000000a0  00 00 00 00 ff 7f 00 00  01 f0 00 00 00 5f 00 00  |............._..|
000000b0  00 00 a2 ff a0 ff 00 00  01 f0 01 00 64 00 00 00  |............d...|
000000c0  00 00 01 f0 00 00 01 70  00 00 8e ff 8c ff 00 ff  |.......p........|
000000d0  0d 00 00 00 20 14 01 00  00 00 00 00 00 00 00 00  |.... ...........|

The Chart file format has a similar byte pattern with the 08AB pattern and looks similar to the BIFF format. We will have to make sure it doesn’t conflict with any signatures so it can be identified separately.

Version 4 of Multiplan was the first to use the BIFF (Binary Interchange File Format). Technically Version BIFF2, not much is know about BIFF1 or if it ever existed. BIFF2 is the exact same format as Excel 2.0 used, so there will be some problems if we want to identify them separately. They currently identify as fmt/55.

hexdump -C MP4.MOD | head
00000000  09 00 04 00 40 01 10 00  42 00 02 00 b5 01 66 00  |....@...B.....f.|
00000010  1b 00 00 00 00 00 00 00  00 00 ff ff 0f 01 00 01  |................|
00000020  00 01 00 01 00 00 00 00  00 00 00 00 00 0d 00 02  |................|
00000030  00 01 00 0e 00 02 00 01  00 0f 00 02 00 00 00 11  |................|
00000040  00 02 00 00 00 2a 00 02  00 00 00 6b 00 13 00 01  |.....*.....k....|
00000050  00 00 00 00 00 fe 0f 00  fe 40 02 e0 3d d0 2f 00  |.........@..=./.|
00000060  01 00 26 00 08 00 00 00  00 00 00 00 e0 3f 27 00  |..&..........?'.|
00000070  08 00 00 00 00 00 00 00  e0 3f 28 00 08 00 00 00  |.........?(.....|
00000080  00 00 00 00 f0 3f 29 00  08 00 00 00 00 00 00 00  |.....?).........|
00000090  f0 3f 70 00 0b 00 00 00  2e 00 02 04 f0 0a 00 f0  |.?p.............|

hexdump -C EXCEL2.XLS | head
00000000  09 00 04 00 02 00 10 00  0b 00 10 00 71 02 00 00  |............q...|
00000010  01 00 29 00 06 03 00 00  dc 0d 00 00 0c 00 02 00  |..).............|
00000020  64 00 0d 00 02 00 01 00  0e 00 02 00 01 00 0f 00  |d...............|
00000030  02 00 01 00 10 00 08 00  fc a9 f1 d2 4d 62 50 3f  |............MbP?|
00000040  11 00 02 00 00 00 22 00  02 00 00 00 40 00 02 00  |......".....@...|
00000050  00 00 2a 00 02 00 00 00  2b 00 02 00 00 00 25 00  |..*.....+.....%.|
00000060  02 00 2c 01 31 00 09 00  c8 00 00 00 04 48 65 6c  |..,.1........Hel|
00000070  76 32 00 0e 00 00 00 00  00 00 00 90 01 00 00 00  |v2..............|
00000080  00 00 8d 31 00 09 00 c8  00 01 00 04 48 65 6c 76  |...1........Helv|
00000090  32 00 0e 00 00 00 00 00  00 00 bc 02 00 00 00 00  |2...............|

You can see in the hex values above a difference of two bytes in the header. The reason the Multiplan file identifies as an Excel 2 file is the PRONOM signature ignores those two bytes and allows them to be anything. Some specifications say these aren’t used, but clearly there is a use for them. We could probably use the same signature for Multiplan, but include the two bytes, then set the priority to the Multiplan signature.

Multiplan 4.2 is very different.

hexdump -C MP42.MOD | head
00000000  0c ef 4d 50 a4 01 00 00  00 00 00 00 00 00 00 00  |..MP............|
00000010  00 00 00 00 00 00 80 02  00 00 00 00 00 00 00 2e  |................|
00000020  ff 0f ff 00 01 00 d0 02  d0 02 a0 05 a0 05 d0 2f  |.............../|
00000030  e0 3d 40 02 09 00 03 00  02 04 0a 00 00 00 fe 0f  |.=@.............|
00000040  00 fe 00 00 01 00 01 00  00 00 00 00 00 00 00 00  |................|
00000050  00 00 00 00 00 00 00 00  01 00 00 00 06 01 15 50  |...............P|
00000060  05 00 00 00 00 00 00 00  06 00 13 00 07 00 07 00  |................|
00000070  00 00 00 00 00 00 08 00  00 00 00 00 00 00 00 00  |................|
00000080  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

The hex values for the first 4 bytes have a similar pattern. 0CEF, Which seems to be in sequence where Version 3 left off. Microsoft calls this new format, New or Normal Binary File Format. They claim it is “the fastest loading and fastest saving file format ever“! Exciting as the new format probably was, it didn’t last long. Multiplan was phased out so Excel could shine.

When I was younger I didn’t use DOS very often because the computer my father brought home in the mid 1980’s was a Macintosh. I use DOS more now in my research then I did when I was younger. Using the DOS interface is not easy. There are a lot of key commands you need to know intuitively just to navigate, but it is fascinating to see how far software has come. Early Excel, Multiplan, and Chart were all intertwined, but hopefully combing through all of these samples can bring some clarity. Take a look at the draft signature I made and all the samples that go with it on my GitHub page.

Composite File Management System

November 3, 2023 by Thor 1 Comment

In honor of World Digital Preservation Day, I wanted to write a little about format headers, the magic that makes some files more easily identifiable than others.

When it comes to binary file formats, some developers decide to make the format clearly identifiable in a header and others choose to make it ambiguous. Others have a little fun with leaving little clues and references to popular culture.

A couple of my favorites based on their header.

Early CoolEdit / Audition files began with the string “COOLNESS”.
Medi8or format with string “MatchWare Medi8or Version 3.00”
MacCaption with string “File Format=MacCaption_MCC V2.0”
HyperWriter format with string “HyperWriter!”
ExpressPublisher and AnFX Java Movie with hex values “CAFEBEEF”
TIFF format which has at bytes 2-3 a “An arbitrary but carefully chosen number (42)“

A couple of my current least favorites:

MP3 format, which can have no header just frames and which clash with everything.
Canvas format which the early versions (CVS) have no standard header.
Leica Cyclone PTS format with just point cloud data, no headers.
Adobe Flash (FLA) later versions where the ZIP container is non standard and throws a Central Directory error.

Like I said some developers make it very obvious what software created the file format and others seem to make things difficult. I understand there is a need to optimize files to keep them from getting bloated and taking up too much space, but many of the size limits from the early days of computing are not an issue anymore. Can’t we be more clear when designing a file format?

Today I want to document one format which was very easy to identify as it spelled out its format very verbosely, but because of the lack of additional documentation makes it very hard to preserve.

Meet the Composite File Management System file format:

hexdump -C sample.br4
00000000  43 43 6d 46 20 2d 20 55  6e 69 76 65 72 73 61 6c  |CCmF - Universal|
00000010  20 2d 20 41 78 69 6f 6d  20 2d 20 41 47 50 20 2d  | - Axiom - AGP -|
00000020  20 43 6f 6d 70 6f 73 69  74 65 20 46 69 6c 65 20  | Composite File |
00000030  4d 61 6e 61 67 65 6d 65  6e 74 20 53 79 73 74 65  |Management Syste|
00000040  6d 20 28 55 6e 69 76 65  72 73 61 6c 29 20 2d 20  |m (Universal) - |
00000050  43 72 65 61 74 65 64 20  62 79 20 41 6e 64 72 65  |Created by Andre|
00000060  61 20 50 65 73 73 69 6e  6f 2c 20 44 65 63 65 6d  |a Pessino, Decem|
00000070  62 65 72 20 31 39 39 35  20 28 76 65 72 73 2e 20  |ber 1995 (vers. |
00000080  35 29 20 2d 20 43 6f 70  79 72 69 67 68 74 28 63  |5) - Copyright(c|
00000090  29 20 31 39 39 35 2d 39  36 20 62 79 20 4d 65 74  |) 1995-96 by Met|
000000a0  61 54 6f 6f 6c 73 2c 20  49 6e 63 2e 20 2d 20 50  |aTools, Inc. - P|
000000b0  72 6f 75 64 6c 79 20 6d  61 64 65 20 69 6e 20 74  |roudly made in t|
000000c0  68 65 20 55 53 41 2c 20  6c 61 6e 64 20 6f 66 20  |he USA, land of |
000000d0  74 68 65 20 66 72 65 65  2c 20 68 6f 6d 65 20 6f  |the free, home o|
000000e0  66 20 74 68 65 20 62 72  61 76 65 2e 00 00 00 00  |f the brave.....|
000000f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

Where to start? First off, this is the Bryce 4 file format. Bryce was a 3D modeling, animation software developed by MetaTools, later MetaCreations. Metacreations was also the developer of popular software Ray Dream Studio/Infini D, Fractal Design Painter, and Kai’s Power Tools.

Secondly, this format refers to a Universal File Management System or CCmF, which I have found to be the file format for many other extensions, some of which are .goo, .brc, .br3, .br4, .br5, .sfp, .shp, .obp. It doesn’t always have the verbose header, some of them have the following:

hexdump -C Tutorial.obp | head
00000000  20 20 20 20 20 20 20 20  20 20 20 20 20 20 20 20  |                |
*
00000050  20 20 20 20 20 20 20 20  20 20 20 20 20 20 43 43  |              CC|
00000060  6d 46 69 6c 65 3a 3a 6b  49 64 65 6e 74 69 66 79  |mFile::kIdentify|
00000070  34 20 20 20 20 20 20 20  20 20 20 20 20 20 20 20  |4               |
00000080  20 20 20 20 20 20 20 20  20 20 20 20 20 20 20 20  |                |

Different, but still contains the CCmF identification string. Others have the verbose header, but further down inside the file.

With this format being used with so many well known software titles, I assumed information on the format would we readily available. Alas, not so much. The format even had the name of the creator! “Created by Andrea Pessino, December 1995”. So I reached out. He was on Twitter and I asked about the file format and if there was any documentation available. Twitter (X) has since deleted his responses after he deleted his account, but he told me he wasn’t sure where the documentation might be. One other developer also commented and confirmed they didn’t know where any of the documentation went after they left.

MetaCreations sold Bryce to Corel in 2000, then in 2004 sold it to Daz3D, the current owners. It’s not actively developed anymore being that it was never made into a 64bit application. A blog post explains the format a little more, but concludes it is a secret known only to Daz.

It seems there is a community who would like to see Bryce more open, maybe even open-sourced. This thread discusses the format and the underlying Axiom format used.

The creator Andrea Pessino was able to track down some documentation on the CCmF file structure for me. He explained Axiom was an entire codebase for all MetaTools/Creations applications and plugins. So the CCmF system was more than a file format. The documentation included some information on versioning of a CCmF.

There seems to be a few versions of the CCmF file structure.

CCmFile::kIdentify which corresponds with December 1995 (vers. 5)
CCmFile::kIdentify2 which corresponds with March 1997 (vers. 7)
CCmFile::kIdentify3 which corresponds with October 1998 (vers. 9)
CCmFile::kDfFormat which is a Generic Composite File

The documentation given to me was up to date for 1998, but after Corel purchased Bryce there was some updates made as many material files have the identifier “CCmFile::kIdentify4“.

Bryce 6 & 7 were released by Daz3D and have a different file header. They have the extension .BR6 & .BR7 with the header:

hexdump -C Bryce7-s01.br7 | head  
00000000  42 72 79 63 65 5f 36 2e  30 5f 46 69 6c 65 00 00  |Bryce_6.0_File..|
00000010  11 00 00 00 d4 07 00 00  00 20 00 00 e5 07 00 00  |......... ......|
00000020  00 0a 00 00 00 10 00 00  00 08 78 9c 63 64 60 60  |..........x.cd``|
00000030  60 04 e2 8c cc f4 0c 85  e4 9c fc d2 14 85 92 d4  |`...............|
00000040  8a 92 d2 a2 54 86 11 05  18 a1 18 04 82 76 c8 b5  |....T........v..|
00000050  be 0e 7c 60 8f 4e 93 67  f2 07 32 f5 d1 0e 30 31  |..|`.N.g..2...01|
00000060  40 fc ca 0c c5 60 bf 33  a2 ab da e2 8c c0 70 e0  |@....`.3......p.|
00000070  00 22 58 a0 9c ff 2a 40  fc bf 16 88 ff c3 c3 2e  |."X...*@........|
00000080  13 64 20 83 82 13 50 29  50 ad 17 50 ef 3c 20 ce  |.d ...P)P..P.< .|
00000090  72 66 64 86 19 31 cd 09  42 57 b9 80 71 43 9d 0b  |rfd..1..BW..qC..|

I still need to gather more samples from the various extensions related to this format and the software related to them. More work to do understanding the different uses of the short CCmFile string and the more detailed header and the differences between objects, materials, and models. When I asked Andrea why he used such a verbose file header, his answer was basically, why not!

Apple Mail

October 27, 2023 by Thor Leave a comment

There really is no “Macintosh Format”, but there sure are a lot of formats you only find on the MacOS. From Resource Forks and iWork formats to unique sound formats, MacOS has them all! Majority of cross-platform software vendors have done a much better job in recent years in making their file formats the same across platforms, but for Apple, they love to make things unique, just for their platform.

Take EMLX for example. Seems to be a trend to add “X” to the end of an older format to breath new life into it. The EML format, or Electronic Mail, has existed for a few decades now, but in 2005 Apple updated their Apple Mail application to use a new format, EMLX.

As far as I know, Apple hasn’t released any documentation on the EMLX format, but many folks out there have asked the question and have been able to “reverse engineer” the format. Lets take a look.

An EMLX file consists of three parts:

bytecount on first line;
email content in MIME format (headers, body, attachments);
Apple property list (plist) with metadata.

The bytecount is a variable number which consists of the total bytes starting from the start of the MIME format, including HTML, to the start of the XML property list. Lets look at a simple EMLX.

The byte count is on line 1 with the MIME email (EML) taking up the 556 bytes, then the XML plist at the end. You may ask, what is a plist? Well, it is another Apple (originally NextStep) invention which is embedded throughout the MacOS operating system. A Plist is usually an XML with keys but can also be in a binary format. The Plist can contain properties of the email within Apple Mail like special color flags, tagged as junk, date received and last reviewed.

If you do happen across an EMLX file or group of them, there are a few tools you can use to convert them to a plain old EML. There are python libraries or many other tools to do the job.

But first we need to be sure of identification beyond the extension. Adding this file format to PRONOM would help in identification for preservation purposes. If ran through PRONOM today we get:

filename : '9.emlx'
filesize : 18582
modified : 2023-10-26T22:16:25-06:00
errors   : 
matches  :
  - ns      : 'pronom'
    id      : 'fmt/950'
    format  : 'MIME Email'
    version : '1.0'
    mime    : 'message/rfc822'
    class   : 'Text (Structured)'
    basis   : 'byte match at [[31 17] [599 4] [339 6] [426 6] [90 14]]'
    warning : 'extension mismatch'

Because the format has a EML plain text format within its structure, it is assumed to be an EML file. While technically accurate, Identifying as a unique EMLX format would be beneficial in a preservation system so you can properly assign risk and choose the right tool to parse or migrate.

In looking at the three parts of an EMLX format, we know the EML file is not a good way to show the difference as they are the same structure. The byte count on the first line is variable, so there is no static byte sequence to use for identification. That leaves the Plist section at the end to distinguish the difference.

The PRONOM entry for a Plist looks for the typical XML strings present in most XML files, but then uses the root element “<plist version=”1.0″>” for identification. We could combine the existing EML signature and the Plist signature to identify an EMLX, or just take the existing EML signature and put in a small byte sequence for the closing of the </plist> tag near the EOF? There would be a need for a priority over EML, both would essentially accomplish the same thing.

Take a look at latter idea on my GitHub page and tell me which makes the most sense.

Common Ground

October 20, 2023 by Thor 1 Comment

If digital preservation had an extension it most likely would be .DP

Unfortunately, it’s taken. Say hello to Digital Paper.

In the early 1990’s, folks started to share documents with each other through the their phone lines. The early internet, BBS, AOL, CompuServe and the like allowed people to share ideas through applications like Word/WordPerfect Documents. Most people had a copy of the popular software and that software could open documents from their competitors, but fonts were always a problem. Technically a font is software as well and needs a license to be used. Also printers at the time dictated what the document might look like when opened, so your document may look different on someone else’s computer. This lead to a few innovations in the software market Digital Paper.

The idea is simple, create a format which could be opened with a free viewer which includes all the parts to make it look and print just like it was intended to. You may have already guessed who the winner in this space tuned out to be, yes, the PDF format. You can’t tell the history of the PDF Format without mentioning others that tried their luck to be the leader in portable document formats . WordPerfect’s Envoy format was one, Common Ground Digital Paper was another.

No Hands Software which started in 1990, developed the idea of making your documents truly portable. They released the Common Ground Maker and Viewer software in 1993. By 1996 the company was doing so well they were bought for $6 million by Hummingbird Ltd. PDF soon became so ubiquitous, formats like Common Ground and Envoy fizzled out. That doesn’t mean they didn’t have a big impact and still can be found in quite a few places.

Apple was one of the bigger users for awhile, but the format can still be found floating around today.

The Common Ground Digital Paper has some similarities to the PDF format, but the biggest different is the format is proprietary and not open like PDF. Another difference is you could embed the viewer into the file, this would make an executable on both Windows and Macintosh. Very convenient for sending to those who may not have the viewer or can’t install the viewer on their system.

Common Ground had two different viewers, a pro viewer with more features and a Mini Viewer with basic features and which was free to download and distribute from their website. Unfortunately, they linked to an FTP site which no longer is available and so finding the viewers today can be difficult.

I came across a boxed version 1 for Macintosh of the software a few years back, but have yet to find other full versions. The software did change hands a bit, but seems to have topped out at Version 4 in the late 1990’s. Let’s take a look at the file format for the samples we do have.

Version 1 for the Macintosh was the first I believe, coming to Windows shortly afterwards. The format was even assigned a MimeType for use on the web and the application gives us a little insight into the format.

The commonground file format does have versions (two at the moment). They *are* internally documented with a file signature, allowing commonground viewers to automatically handle both old and new format files. Therefore, I don’t believe a ‘version’ parameter is needed.

A Content-Type of “application/commonground” indicates a document in the Common Ground portable file format, also known as Digital Paper.

Encoding considerations: Common Ground files are in a binary format. Some encoding will be necessary for MIME mailers as in application/octet-stream. Common Ground files for the Macintosh are encoded in the data fork of a Macintosh file. The file type is APPL, the creator is CGVM.

If we look at a sample from Version 1 for the Macintosh we find the follow hex values:

hexdump -C CG-s01.dp | head
00000000  00 00 03 56 00 00 04 d9  43 47 44 43 00 00 00 00  |...V....CGDC....|
00000010  96 6c 00 07 04 b4 03 de  00 00 00 00 02 da 02 28  |.l.............(|
00000020  00 11 02 ff 0c 00 ff ff  ff ff 00 00 00 00 00 00  |................|
00000030  00 00 02 28 00 00 02 da  00 00 00 00 00 00 00 01  |...(............|
00000040  00 0a 00 05 00 05 00 15  02 23 00 32 00 05 80 02  |.........#.2....|
00000050  00 15 7f fe 00 2c 00 09  00 03 06 47 65 6e 65 76  |.....,.....Genev|
00000060  61 00 00 03 00 03 00 0d  00 0c 00 2e 00 04 00 00  |a...............|
00000070  00 00 00 2b 06 11 07 54  65 73 74 69 6e 67 00 01  |...+...Testing..|
00000080  00 0a ff e1 ff e2 02 f9  02 46 00 03 00 00 00 0d  |.........F......|
00000090  00 00 00 28 02 d5 01 05  05 2d 20 31 20 2d 00 ff  |...(.....- 1 -..|

In all the samples I have the first 8 bytes are not consistent, but the next four bytes are. CGDC, which happens to be the registered type on the Macintosh. Convenient. But it appears later versions are not the same.

hexdump -C MANUAL.DP | head
00000000  00 00 00 20 00 00 b7 f4  44 50 4c 33 00 00 00 04  |... ....DPL3....|
00000010  00 00 00 00 00 00 00 00  3b 60 53 df 00 00 00 00  |........;`S.....|
00000020  00 00 00 18 00 00 b4 da  00 00 b4 c2 00 00 03 3e  |...............>|
00000030  78 00 79 00 7a 00 7b 00  00 00 00 77 01 01 00 0c  |x.y.z.{....w....|
00000040  00 01 02 01 00 00 00 97  fe ed f0 05 00 b7 86 04  |................|
00000050  5f 05 f7 01 00 03 ed f0  02 00 3d 00 ff 45 75 72  |_.........=..Eur|
00000060  6c 20 00 01 07 ff bf 05  9f 00 01 08 a3 05 fb ba  |l ..............|
00000070  02 fa f1 00 ff ff 00 11  ff 68 74 74 70 3a 2f 2f  |.........http://|
00000080  77 ff 77 77 2e 47 53 50  2e 43 b9 43 1c 0f 03 04  |w.ww.GSP.C.C....|
00000090  95 05 c8 0d 00 cc fb 05  e3 13 06 15 6d 61 69 6c  |............mail|

hexdump -C dpwhite.dp | head
00000000  00 00 00 18 00 01 79 17  44 50 4c 32 00 00 00 00  |......y.DPL2....|
00000010  00 00 00 00 00 00 00 00  00 00 00 18 00 01 76 de  |..............v.|
00000020  00 01 76 c6 00 00 04 b2  00 00 00 00 00 00 00 00  |..v.............|
00000030  00 00 00 1e 01 01 00 0c  00 00 01 01 00 00 00 12  |................|
00000040  00 01 00 01 00 00 00 00  0c 4e 09 60 01 2c 01 2c  |.........N.`.,.,|
00000050  00 64 00 00 00 02 00 00  00 00 00 a2 01 01 00 0c  |.d..............|
00000060  00 01 02 01 00 00 00 e2  fa ed f0 22 ed f1 0c 4e  |..........."...N|
00000070  09 60 00 ff e1 01 26 0a  83 08 3b ff ff 6a ff 6a  |.`....&...;..j.j|
00000080  0c e4 09 f6 01 ff 2c 01  2c 00 08 00 64 00 df 00  |......,.,...d...|
00000090  01 01 00 03 ed f0 0f 00  79 0a 1c 0f 28 07 42 41  |........y...(.BA|

These files are from a later version and have a different string at byte 8. DPL2 & DPL3. In the MiniViewer you can request document information and it provides some basic metadata for each file.

I only have one example of the DPL3, but a couple examples of DPL2, and it seems like DPL2 comes from a Version 3 DP Maker and DPL3 comes from Version 4 Maker. Need to see if I can find a Version 2 file and see if it follows the same pattern.

Two of my favorite CD-ROM’s on Internet Archive are Dr. Dobb’s The Essential Books on File Formats and Internet File Formats, both have copies of the Mini Viewer.

One of features similar to PDF is the ability to password protect certain features. This is what the document information looks like.

The header is the same, but the plain text usually seen in the file is no longer visible, so it appears the rest of the file is encrypted.

hexdump -C password.dp | head 
00000000  00 00 5d 95 00 00 06 94  43 47 44 43 00 00 00 01  |..].....CGDC....|
00000010  8e 3b 18 7e c5 16 f8 e0  0f f5 6f 32 2f 34 36 81  |.;.~......o2/46.|
00000020  4b 8a 03 da 9e 1a 85 6c  36 e4 39 f2 5a 2a a2 5f  |K......l6.9.Z*._|
00000030  81 83 65 ee 9c 16 d0 2d  2d c3 04 df 69 c8 06 0d  |..e....--...i...|
00000040  77 df 27 19 33 59 f6 05  61 4e 2c a6 58 27 47 26  |w.'.3Y..aN,.X'G&|
00000050  fe 6b 3c 06 7e cb 7f fb  33 f8 64 ed 05 54 b4 7d  |.k<.~...3.d..T.}|
00000060  c7 b5 e3 c2 df 40 53 63  ef 8e 10 1c c7 58 bd 28  |.....@Sc.....X.(|
00000070  9b 8a 2c 8f ae 82 33 f7  ff d4 3c 96 5c b4 08 69  |..,...3...<.\..i|
00000080  1f 00 af ce a7 56 93 27  07 cc 39 97 17 22 49 d7  |.....V.'..9.."I.|
00000090  5b 89 9b e6 b7 b1 5c 38  75 ba 08 ee 66 d0 9a d2  |[.....\8u...f...|

This file format is not currently in PRONOM. From what I have gathered I could add three signatures. There could be some other variations out there and the password protection needs to be considered. Maybe I’ll take Nick Gault’s offer and request the format which was available starting in the middle of 1995. Think they’ll deliver?

No bad deed….

October 13, 2023 by Thor Leave a comment

I had access to my first Macintosh computer around 1987. My father brought it home and I spent hours on it playing games and occasionally writing reports for school. The Macintosh Plus computer had one floppy drive and no hard drive. I remember playing the game Orbiter which had two floppy disks and right in the middle of game play it would pause and ask me to insert disk 2, then quickly ask for disk 1 again. The struggle was real. I spent years using many different Macintosh computers and now own more than I wish to admit. I’m preserving them!

The wild world of digital preservation has been a little lacking on the Macintosh side of things as I have come to realize. There still not a great way to manage Resource Forks in many preservation systems and the identification tools are mainly focused on the data bytetreams and not any system specific attributes Macintosh used often.

The PRONOM registry has either referenced early Macintosh specific formats or missed them entirely so I have been slowly working on a few to close that gap.

Interestingly enough, many Microsoft programs initially made their GUI debuts on the early Macintosh before making their way to Windows. Excel is one I am working on, as Version 1 is not identifiable in PRONOM, it was Macintosh only at the time.

Another is PowerPoint, I recently submitted two new signatures to PRONOM.

fmt/1747: Microsoft PowerPoint Presentation v2.x. Full entry added.
fmt/1748: Microsoft PowerPoint Presentation v3.x. Full entry added.
fmt/1866: Microsoft Powerpoint for Macintosh v.2. Full entry added.
fmt/1867: Microsoft Powerpoint for Macintosh v.3. Full entry added.

PowerPoint was initially released in 1987 on the Macintosh platform. It was developed by a company called ForeThought. Version 1.0 on the Macintosh was under this name, until it was bought by Microsoft only three months after being released. The history of PowerPoint can be discovered at Robert Gaskins, one of the original developers, website and book he wrote. The available information provided by Microsoft is only for the OLE format, covering versions 4.0 until 2003.

So, lets take a look at the Powerpoint original file format, before OLE.

   Type/Creator      RF      DF  Date         Filename
f  SLDS/PPNT         0       932 Oct 10 19:10 PowerPoint-v1

Luckily the early PowerPoint files did not have a Resource Fork. The Data Fork, if you haven’t noticed, has an interesting set of hex values at the beginning of the file. 0BADDEED is the first 4 bytes. If we look at a PowerPoint version 2 file from Windows.

The file format is the same, but because of the weird world of endianness, the first few bytes are in reverse order, EDDEAD0B.

Obviously we need to discuss this magic number and the meaning behind “Bad Deed”. This question was asked previously by the digital preservation community. I have a previous blog post about the use of words for the magic number CAFEBEEF as it was used with with JAVA class files and Express Publisher in the 1990’s. BADDEED looks like another clever use of the hex values that formed words. But was there a story behind the words? Joe Carrano asked if this string might be hexspeak. I wanted to know more so I asked some one who might know.

Robert Gaskins was kind enough to chat with me for a bit about the early days of PowerPoint.

I had a theory on the possible meaning behind BADDEED, so I asked him what the feeling was like between Apple and Microsoft at the time. I had heard for years that PowerPoint was originally created for the Macintosh, but Robert informed me:

In fact, PowerPoint was designed first for Microsoft Windows,

and its first spec shows that: “All the screen shots, menus, and

dialogs were set up to look like Microsoft Windows, not like

Macintosh.” (Gaskins, Sweating Bullets, p. 92) You can see that

spec here.

A year later, we concluded that we would be forced to ship

on Mac first, although we still thought that Windows was the

big opportunity and thought that Mac was risky. “We just didn’t think

we could successfully ship a product for Windows, yet, though we planned

to later. (Gaskins, Sweating Bullets, p. 105) The considerations are

summarized in my June 1986 product marketing document.

Of course, we turned out to have been right all along. PowerPoint on

Mac was much loved, but sales remained poor because Mac sales were

so poor. It was only after we shipped on Windows that PowerPoint gained

the dominant market share which has characterized it ever since, and

Windows PPT outsold Mac PPT very quickly. (Gaskins, Sweating Bullets, p. 403)

So my original thought was that there was some bad feelings around this Apple, Microsoft battle which has been the sentiment for quite some time. So when I asked if any of that influenced the use of BADDEED, I was told:

So, far from being disgruntled by expanding PowerPoint to Windows,

that had been our goal all along, and its achievement was the most

important success we had.

I judge that you are fully aware of all that, and that

your question is more, “was there any bad deed signified

by the Mac hex value chosen?” No, it was just the poverty

of choice when you only have six letters.

So there you have it. The use of the hex values 0x0BADDEED, was simply chosen from a limited set of values when looking at words hexadecimal could spell. I guess I should never let the truth get in the way of a good story.

I continued to have a wonderful conversation with Robert and also asked him for some details on the rest of the PowerPoint file format. I was hoping there might be some documentation out there explaining the early format before Microsoft took over. Robert said:

I don’t know of any such documentation apart from the official

Microsoft support files available online. I don’t have any such

information. I know that Dennis Austin deposited some of our

working files at the Computer History Museum (not online):

https://archive.computerhistory.org/resources/access/text/finding-aids/102733943-Austin/102733943-Austin.pdf

and it’s likely that some information is there–if nothing

else, it claims to contain a source code listing for PPT 1.0

which would contain the code to read the file format.

So there might be some information in at the Computer History Museum worth looking into.

As far as I could tell from the available online information, there is a few differences between Version 1.0 and Version 2.0, the biggest being the fact that 1.0 did not have an option to print in color, amount a few other minor things. Here is a screenshot of a page from the Microsoft PowerPoint 2.0 documentation on archive.org.

I suppose with the signature additions of the Macintosh and Windows versions 2.0 and 3.0 of the PowerPoint file format in PRONOM, that should cover most needs. Currently my PowerPoint 1.0 files identify at 2.0 files, so I may need to have them adjust the PUID to include both versions 1.0 and 2.0 as they are so similar. If I am able to find a difference or get my hands on the original source code I may find a better solution.

Quicktime MooV

October 6, 2023 by Thor 2 Comments

During the 1990’s Apple Quicktime became the dominant digital media standard. It is the basis for the MPEG-4 format which is used everywhere now. Technically the Quicktime Movie format is a container or wrapper which can hold a variety of Video and Audio streams.

The basic unit of a Quicktime Movie is an atom. The MooV atom is the most important piece of a Quicktime Movie. Without it and the “mvhd” header atom, all the characteristics of the movie are lost.

Having the MooV atom missing from your movie file seems like it would be a rare thing, but it may happen more often than you think.

What happens when you come across a Quicktime file on an HFS disk, like one of these: https://archive.org/details/quick-clips-cd

If you try and open the movie you might see this.

MediaInfo doesn’t know what to make of the file. You can see the hex values from the beginning of the file, there clearly is no MooV atom.

Enter Macintosh Resource Forks.

Original Quicktime files stored the MOOV atom in a resource fork.

Lets take a look a closer look at one of these files.

derez Wildebeest 
data 'moov' (128) {
	$"0000 0465 6D6F 6F76 0000 006C 6D76 6864"            /* ...emoov...lmvhd */
	$"0000 0000 E143 7EF5 E143 7EF5 0000 0258"            /* ....?C~??C~?...X */
	$"0000 1068 0001 0000 00FF 0000 0000 0000"            /* ...h.....?...... */
	$"0000 0000 0001 0000 0000 0000 0000 0000"            /* ................ */
	$"0000 0000 0001 0000 0000 0000 0000 0000"            /* ................ */
	$"0000 0000 4000 0000 0000 0000 0000 0000"            /* ....@........... */
	$"0000 0924 0000 0000 0000 0000 0000 0000"            /* ...$............ */
	$"0000 0002 0000 03D9 7472 616B 0000 005C"            /* .......?trak...\ */
	$"746B 6864 0000 000F A5EA 1D89 E143 7EF5"            /* tkhd....??.??C~? */
	$"0000 0001 0000 0000 0000 1068 0000 0000"            /* ...........h.... */
	$"0000 0000 0000 0000 0000 0000 0001 0000"            /* ................ */
	$"0000 0000 0000 0000 0000 0000 0001 0000"            /* ................ */
	$"0000 0000 0000 0000 0000 0000 4000 0000"            /* ............@... */
	$"00A0 0000 0078 0000 0000 0024 6564 7473"            /* .?...x.....$edts */
	$"0000 001C 656C 7374 0000 0000 0000 0001"            /* ....elst........ */
	$"0000 1068 0000 0000 0001 0000 0000 0351"            /* ...h...........Q */
	$"6D64 6961 0000 0020 6D64 6864 0000 0000"            /* mdia... mdhd.... */
	$"E143 7EF5 E143 7EF5 0000 0258 0000 1068"            /* ?C~??C~?...X...h */
	$"0000 003C 0000 003A 6864 6C72 0000 0000"            /* ...<...:hdlr.... */
	$"6D68 6C72 7669 6465 6170 706C 4000 0000"            /* mhlrvideappl@... */
	$"0001 002C 1941 7070 6C65 2056 6964 656F"            /* ...,.Apple Video */
	$"204D 6564 6961 2048 616E 646C 6572 0000"            /*  Media Handler.. */

The MooV atom is in the Resource Fork. Apple explains why they did it this way.

FILE MOVIE HEADER

Note: the header is safer when stored at the beginning of the file or in the HFS resource fork as type ‘moov’; ID any. The advantage of using another file fork is that the header can be lengthened without recalculating the sample offsets or new header must be written at the end of the file.
QTM-Layout

If you are playing back a movie on an older Macintosh using an earlier version of Quicktime, you won’t have any issues, but if you plan on playing the movie on a newer system or try and preserve the file, then we run into problems. Especially if the file is moved off of the HFS disk onto a system which doesn’t maintain the resource fork. Then you are stuck with just the data with no way to interpret the movie file.

Solutions.

One solution you can follow is to use MacBinary or AppleSingle to combine the Resource Fork and Data Fork together into one file. You are left with a different format, but one which can be preserved and reverted back to the original when needed.

Another way is to create a Single-Fork Movie file, aka a normal QuickTime file.

“single-fork movie file – A QuickTime movie file
that stores both the movie data and the movie
resource in the data fork of the movie file. You
can use single-fork movie files to ease the
exchange of QuickTime movie data between
Macintosh computers and other computer
systems.”
Inside Macintosh – QuickTime

Creating a Single-Fork can be accomplished a couple different ways. One is to use an older version of QuickTime to “Save As” to a self contained file with the box checked to allow playback on a “non-Apple” computer.

Another method is to use a simple utility called Single Fork Flattener. I found a copy on a old QuickTime disc and uploaded to Macintosh Garden if you want to try it out. No QuickTime needed, just open the file and it updates it to include the MooV resource. Also a tool called FlattenMooV.

Once combined, MediaInfo now sees a complete QuickTime file which VLC can play!

mediainfo Wildebeest2 
General
Complete name                            : Wildebeest
Format                                   : QuickTime
Format/Info                              : Original Apple specifications
File size                                : 565 KiB
Duration                                 : 7 s 0 ms
Overall bit rate                         : 661 kb/s
Frame rate                               : 10.000 FPS
Encoded date                             : 2023-10-02 14:15:15 UTC
Tagged date                              : 2023-10-02 14:15:15 UTC
Writing library                          : Apple QuickTime
FileExtension_Invalid                    : braw mov qt

Video
ID                                       : 0
Format                                   : Road Pizza
Codec ID                                 : rpza
Duration                                 : 7 s 0 ms
Bit rate                                 : 659 kb/s
Width                                    : 160 pixels
Height                                   : 120 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Constant
Frame rate                               : 10.000 FPS
Bits/(Pixel*Frame)                       : 3.434
Stream size                              : 563 KiB (100%)
Language                                 : English
Encoded date                             : 1992-03-16 09:40:25 UTC
Tagged date                              : 2023-10-02 14:15:15 UTC

I was hoping I could find a method to use a modern tool to combine into a Single-Fork file, ~~but nothing yet~~. I did find a C++ source that when compiled does indeed merge the two forks together, which in this case merges the MooV atom at the end of the file. Its called qtmerge. QuickTime 7 is your best bet for a GUI tool which works on recent MacOS, but not the last couple versions. There is a reference out there to a tool called RezWack, but I have been unable to verify.

BINHEX

September 29, 2023 by Thor 1 Comment

Working with files in todays world is much different than before. Today getting files back and forth from the cloud or through email is relatively easy, unlike the early days when we used FTP sites and needed to encode our data to properly transfer. I remember using an FTP program on my old Mac called Fetch. We had to determine if the content was to be transferred as text or binary.

Picking the right encoding was critical to getting the content transferred correctly, this was even more critical when working with Macintosh files which needed a resource fork and/or finder attributes to work properly. In those cases a MacBinary or BinHex file was required! Fetch would automatically identify those formats and decode them for you.

If you need a refresher on MacBinary and AppleSingle, you can view my iPres 2022 presentation.

One format I didn’t spend much if any time on is the BinHex format. BinHex was a format born out of necessity to move files back and forth across the World Web Web, bulletin boards, AOL, Compuserve, and the like. The FTP program Fetch glossary describes BinHex as:

BinHex (sometimes called BinHex4) is a format for representing a Macintosh file in text form.

The Macintosh file is converted to a series of lines, each made up of letters, numbers, and

punctuation. Because BinHex files are simply text, they can be sent through most electronic mail

systems and stored on most computers. However the conversion to text makes the file larger, so it

takes longer to transmit a file in BinHex format than if the file was represented some other way.

The suffix “.hqx” usually indicates a BinHex format file.

You can still find many of these HQX files floating around the interwebs and on older CDs from the 1990’s. One such CD recently came into my possession. I managed to get a copy of the book “Internet File Formats“, by Tim Kientzie. It came with a CD-ROM with lots of goodies included. Some sample files, specifications, and software. The disc itself is an ISO 9660 partitioned disc, but includes a few Macintosh formats, so the author put many of the software files in the HQX format to maintain the much needed resource fork Macintosh applications need in order to run.

I initially ran the whole disc through DROID to get an idea what was on the disc and if any sample formats were unidentified (something I do regularly), and found majority of the HQX files didn’t identify as they should have to PRONOM PUID x-fmt/416. The signature is an older one, from 2010, but since the format isn’t updated anymore it should be solid. Or so I thought.

Since BINHEX files are encoded as text, lets take a look at a couple of these from the disc which didn’t identify.

The PRONOM signature currently is:

File extension: hqx	
Name	BinHex Binary Text
Description	Header: (This file must be converted with BinHex
Byte sequences	
Position type	Absolute from BOF
Offset	0	 
Value	28546869732066696C65206D75737420626520636F6E76657274656420776974682042696E486578

That “Value” listed in hexadecimal decodes to: “(This file must be converted with BinHex” as listed in the description. We can see this line in the file above, but the signature assumes the value begins at offset 0 from the beginning of the file. So its looking for that value at the start of the file, but this file seems to have some additional text before the value. What does the specs say?

The BinHex 4.0 format was created in 1985 and defined in RFC 1741.

   The whole file is considered as a stream of bits.  This stream will
   be divided in blocks of 6 bits and then converted to one of 64
   characters contained in a table.  The characters in this table have
   been chosen for maximum noise protection.  The format will start
   with a ":" (first character on a line) and end with a ":".
   There will be a maximum of 64 characters on a line.  It must be
   preceded, by this comment, starting in column 1 (it does not start
   in column 1 in this document):

    (This file must be converted with BinHex 4.0)

   Any text before this comment is to be ignored.

   The characters used is:

    !"#$%&'()*+,- 012345689@ABCDEFGHIJKLMNPQRSTUVXYZ[`abcdefhijklmpqr

Ok, so in the specs we can see the “Value” string must be there, but according to the specification, any text before this comment is to be ignored. So adding some instructions and even an email header at the beginning is ok, as long as the value string is there right before the encoded data.

We also learn a couple interesting things. The first character of the first line after the string should be a “:” and the last line should end with a “:” as well. That could help make the signature more solid. We also learn there are a maximum of 64 characters per line. The last line will probably not have full maximum, but the previous lines should…. I wonder if we could use this fixed position from the initial “:” to add even more strength to the signature.

So an updated PRONOM signature might look like:

BOF: {0-4084}28546869732066696C65206D75737420626520636F6E76657274656420776974682042696E486578{6-9}3A

EOF: 3A (Max Offset 64)

Adding the 4,084 bytes at the beginning allow for additional text. This value worked for my samples but there could be others out there with more. The {6-9} bytes in between the string and the colon account for the various way newlines are encoded. Sometimes is one “0A” byte, other times it is “OD”, and others its both. After testing, adding values in the signature to account for the 64 byte line can fail if the file has only one line, so I left it out.

The EOF should just be the colon (3A), but I found many of my samples had various line endings and other random characters. Hence the 64 bytes for max offset.

Also, the current PRONOM entry doesn’t include the Mime-Type, which is: “application/mac-binhex40”

Hopefully this update will add some strength to the signature and follow the specification closer. The new signature even works on files with extra content at the beginning!

This image has an empty alt attribute; its file name is long-binhex-header.png

There are a number of software titles you can use to encode and decode a BinHex file. On a modern Mac, try using The Unarchiver, or Stuffit Expander. From the commandline, you can use the macutil library or the CLI version of Unarchiver. Although the MacOS has a built in utility to decode BinHex files. If you are using a classic version of Macintosh OS, you can find a number of utilities on Macintosh Garden.

Oh, and also, the CD-ROM I mentioned earlier has a few “fun” features. Not sure if they are on purpose or if errors were made during mastering, but a few filenames have some hidden extra characters and one folder puts any tool traversing the directory into a loop, even droid. Have fun!

Gone in a Flash

September 22, 2023 by Thor Leave a comment

This week I am at the annual iPres digital preservation conference. It is an amazing week of meeting colleagues and old friends who share the same passion of digital preservation. Outside of this community and my co-workers, talking about file formats and digital preservation usually bores people to death and I can hear some of them mumble under their breath, “nerd”! I term I am happy to accept.

At the conference, which is in lovely Urbana-Champaign Illinois this year, I am trying to soak in all the amazing talks and conversations about the challenges facing our work. There were a couple great workshops on Persistent Identifiers and Digital Object Storage Criteria. The presentations I made were of course on File Formats, documentation, and obsolescence. One talk before my panel conversation was about the ubiquitous Adobe Flash format.

The paper, “Around for Decades, Gone in a Flash: How we dealt with Flash objects and the National Archives of the Netherlands” was presented by Lotte Wijsman and Marin Rappard. They knew they had flash objects in their web archives and wanted to go through the process of how they might be preserved and accessed. They started out looking for any files with “FLA”, “SWF”, and “FLV” as extensions. This proved problematic as there were references to those extensions within other documents and objects. They then used DROID to identify the flash formats. “SWF” has quite a number of format PUID’s.

PUID	Format Name	Format Version	Extension
fmt/104	Macromedia Flash	1	swf,
fmt/105	Macromedia Flash	2	swf,
fmt/106	Macromedia Flash	3	swf,
fmt/107	Macromedia Flash	4	swf,
fmt/108	Macromedia Flash	5	swf,
fmt/109	Macromedia Flash	6	swf,
fmt/110	Macromedia Flash	7	swf,
fmt/505	Adobe Flash	8	swf,
fmt/506	Adobe Flash	9	swf,
fmt/507	Adobe Flash	10	swf,
fmt/757	Adobe Flash	11	swf,
fmt/758	Adobe Flash	12	swf,
fmt/759	Adobe Flash	13	swf,
fmt/760	Adobe Flash	14	swf,
fmt/761	Adobe Flash	15	swf,
fmt/762	Adobe Flash	16	swf,
fmt/763	Adobe Flash	17	swf,
fmt/764	Adobe Flash	18	swf,
fmt/765	Adobe Flash	19	swf,
fmt/766	Adobe Flash	20	swf,
fmt/767	Adobe Flash	21	swf,
fmt/768	Adobe Flash	22	swf,
fmt/769	Adobe Flash	23	swf,
fmt/770	Adobe Flash	24	swf,
fmt/771	Adobe Flash	25	swf,
fmt/772	Adobe Flash	26	swf,
fmt/773	Adobe Flash	27	swf,
fmt/774	Adobe Flash	28	swf,
fmt/775	Adobe Flash	29	swf,
fmt/776	Adobe Flash	30	swf,

Even the Macromedia/Adobe Flash Video format has a PRONOM PUID, x-fmt/382.

The format missing from PRONOM is the FLA format. FLA is the native format for Macromedia/Adobe Flash for saving the source project of your Flash document. SWF files are compiled from the FLA source. This means the the SWF will be the most common format found on the web and in public places, but the FLA format might be more often found on local drives and working folders.

The Flash format and software was actually created by Future Wave software in 1996 as FutureSplash Animator, but was shortly bought by Macromedia later that year and Flash 1.0 was born. FutureSplash used the extension .SPA, but Macromedia changed it to FLA.

The format was initially based on the Microsoft Compound File Format or the OLE container format.

oledir Flash4-S01.fla 
oledir 0.54 - http://decalage.info/python/oletools
OLE directory entries in file Flash4-S01.fla:
----+------+-------+----------------------+-----+-----+-----+--------+------
id  |Status|Type   |Name                  |Left |Right|Child|1st Sect|Size  
----+------+-------+----------------------+-----+-----+-----+--------+------
0   |<Used>|Root   |Root Entry            |-    |-    |1    |5       |4416  
1   |<Used>|Stream |Contents              |2    |-    |-    |6       |4013  
2   |<Used>|Stream |Page 1                |-    |-    |-    |0       |329   
3   |unused|Empty  |                      |-    |-    |-    |0       |0     
----+----------------------------+------+--------------------------------------
id  |Name                        |Size  |CLSID                                 
----+----------------------------+------+--------------------------------------
0   |Root Entry                  |-     |597CAA70-72AA-11CF-831E-524153480000  
1   |Contents                    |4013  |                                      
2   |Page 1                      |329   |

The FLA format stayed with OLE until Adobe Flash CS5, which the format changed to use a ZIP container to store all the content.

Flash5.5-S01.fla
Type = zip
Physical Size = 216632

   Date      Time    Attr         Size   Compressed  Name
------------------- ----- ------------ ------------  ------------------------
2022-07-09 11:57:46 .....           25           25  mimetype
2022-07-09 11:57:46 .....            9            9  Flash5.5-S01.xfl
2022-07-09 11:57:46 D....            0            0  LIBRARY
2022-07-09 11:57:46 D....            0            0  META-INF
2022-07-09 11:57:46 .....        49267         3936  DOMDocument.xml
2022-07-09 11:57:48 .....         9735         1103  META-INF/metadata.xml
2022-07-09 11:57:48 .....         8093         2222  PublishSettings.xml
2022-07-09 11:57:48 .....            0            0  MobileSettings.xml
2022-07-09 11:57:48 D....            0            0  LIBRARY/Mouth shape graphic symbols
2022-07-09 11:57:48 D....            0            0  LIBRARY/Voice
2022-07-09 11:57:48 .....       151006       151006  bin/M 1 1252032698.dat
2022-07-09 11:57:48 .....        99707        15311  LIBRARY/mouth.xml
2022-07-09 11:57:48 .....        16510         4534  LIBRARY/Mouth shape graphic symbols/A I.xml
2022-07-09 11:57:48 .....        14334         4086  LIBRARY/Mouth shape graphic symbols/C D G K N R S Th Y Z.xml
2022-07-09 11:57:48 .....        14531         4040  LIBRARY/Mouth shape graphic symbols/E.xml
2022-07-09 11:57:48 .....        15846         4007  LIBRARY/Mouth shape graphic symbols/F V D Th.xml
2022-07-09 11:57:48 .....        13093         3542  LIBRARY/Mouth shape graphic symbols/L D Th.xml
2022-07-09 11:57:48 .....         2106          751  LIBRARY/Mouth shape graphic symbols/M B P Closed.xml
2022-07-09 11:57:48 .....        14130         3949  LIBRARY/Mouth shape graphic symbols/O.xml
2022-07-09 11:57:48 .....        11082         2951  LIBRARY/Mouth shape graphic symbols/Open_Rest.xml
2022-07-09 11:57:48 .....        14847         4066  LIBRARY/Mouth shape graphic symbols/U.xml
2022-07-09 11:57:48 .....         8139         2202  LIBRARY/Mouth shape graphic symbols/W Q.xml
2022-07-09 11:57:48 .....        15768         3914  LIBRARY/panda.xml
2022-07-09 11:57:48 .....        10477         1064  LIBRARY/sample graph.xml
2022-07-09 11:57:48 .....          538          538  bin/SymDepend.cache
------------------- ----- ------------ ------------  ------------------------
2022-07-09 11:57:48             469243       213256  21 files, 4 folders

The move to a ZIP container included a new format, XFL. This XFL file is a simple text file with the text “PROXY-CS5″. In the DOMDocument.xml file we find an XML namespace, xmlns=”http://ns.adobe.com/xfl/2008/” and a version of the XFL structure, xflVersion=”2.1″.

This ZIP compressed FLA file is still being used in the current Adobe Animate software, which no longer uses the flash technology and uses more modern web formats like HTML5 to display the animations.

I took each version and made a PRONOM signature, which you can find here with samples. These container signatures should cover all the major changes for the format, but there is a problem……..

Listing archive: Flash5.5-S01v5.fla

--
Path = Flash5.5-S01v5.fla
Type = zip
ERRORS:
Headers Error
Physical Size = 216581
Embedded Stub Size = 63
Characteristics = Local

   Date      Time    Attr         Size   Compressed  Name
------------------- ----- ------------ ------------  ------------------------
2022-07-09 11:57:46 .....           25           25  mimetype
2022-07-09 11:57:46 D....            0            0  LIBRARY
2022-07-09 11:57:46 D....            0            0  META-INF
2022-07-09 11:57:46 .....        48556         3742  DOMDocument.xml
2022-07-09 11:57:48 .....        10133         1112  META-INF/metadata.xml
2022-07-09 11:57:48 .....         8115         2219  PublishSettings.xml
2022-07-09 11:57:48 .....            0            0  MobileSettings.xml
2022-07-09 11:57:48 D....            0            0  LIBRARY/Mouth shape graphic symbols
2022-07-09 11:57:48 D....            0            0  LIBRARY/Voice
2022-07-09 11:57:48 .....       151006       151006  bin/M 1 1252032698.dat
2022-07-09 11:57:48 .....        99551        15319  LIBRARY/mouth.xml
2022-07-09 11:57:48 .....        16580         4536  LIBRARY/Mouth shape graphic symbols/A I.xml
2022-07-09 11:57:48 .....        14404         4089  LIBRARY/Mouth shape graphic symbols/C D G K N R S Th Y Z.xml
2022-07-09 11:57:48 .....        14531         4044  LIBRARY/Mouth shape graphic symbols/E.xml
2022-07-09 11:57:48 .....        15848         4008  LIBRARY/Mouth shape graphic symbols/F V D Th.xml
2022-07-09 11:57:48 .....        13024         3546  LIBRARY/Mouth shape graphic symbols/L D Th.xml
2022-07-09 11:57:48 .....         2106          752  LIBRARY/Mouth shape graphic symbols/M B P Closed.xml
2022-07-09 11:57:48 .....        14200         3955  LIBRARY/Mouth shape graphic symbols/O.xml
2022-07-09 11:57:48 .....        11152         2963  LIBRARY/Mouth shape graphic symbols/Open_Rest.xml
2022-07-09 11:57:48 .....        14777         4069  LIBRARY/Mouth shape graphic symbols/U.xml
2022-07-09 11:57:48 .....         8287         2228  LIBRARY/Mouth shape graphic symbols/W Q.xml
2022-07-09 11:57:48 .....        15768         3914  LIBRARY/panda.xml
2022-07-09 11:57:48 .....        10477         1064  LIBRARY/sample graph.xml
2022-07-09 11:57:48 .....          538          538  bin/SymDepend.cache
2022-07-09 11:57:46 .....           25           25  mimetype
2022-07-09 11:58:18 .....            9            9  Flash5.5-S01v5.xfl
------------------- ----- ------------ ------------  ------------------------
2022-07-09 11:58:18             469112       213163  22 files, 4 folders

Turns out majority of the samples I have from many versions of Adobe Flash after CS5 have a ZIP Header error. When using the new signatures in DROID, the samples with the header errors will fail in the DROID’s zip library processing. The DROID logs shows this issue:

Could not process the potential container format (ZIP): file:///Flash5.5-S01v5.fla	
Expected 25 more entries in the Central Directory!

The Central Directory header in a ZIP file is quite important to the proper function of the ZIP container. Wikipedia has a great explanation of the header. You may notice in the listing above the file “mimetype” is shown twice which is probably the extra entries the parser wasn’t expecting.

So currently the identification of majority of these FLA formats is on hold until a way is discovered to ignore the error and continue the container identification in DROID.

TIFF

September 15, 2023 by Thor 1 Comment

Lets talk TIFF, or Tagged Image File Format. It is well documented and accepted by the community. The format has been around since 1986, first developed by Aldus as a image format for scanners. The TIFF format is now used worldwide as a preferred format for scanning and preservation of cultural heritage objects.

As amazing as the format is, there are a few features of the format which can be a preservation risk. I want to focus on three of those risks.

The Tagged Image File Format has a well known header:

A TIFF file begins with an 8-byte image file header, containing the following
information:
Bytes 0-1: The byte order used within the file. Legal values are:
“II” (4949.H) LSB (IBM)
“MM” (4D4D.H) MSB (Mac)
Bytes 2-3 An arbitrary but carefully chosen number (42).
Bytes 4-7 The offset (in bytes) of the first IFD.

Putting this poster of the TIFF structure in your office will impress your co-workers, guaranteed. Thanks Ange!

The three risks I have been pondering lately are:

Multiple IFD’s
Metadata
DNG format

TIFF version 6.0 was released in 1992 and is the most recent version. Although some vendors are free to add their own private tags. In 1995 Adobe added an addendum which added some additions for use with PageMaker.

One of the main features of the TIFF format is its ability to hold multiple pages. In Adobe’s words:

TIFF has always supported what amounts to a singly linked list of IFD’s in a single TIFF file, via the “next IFD pointer,” though most applications currently ignore any IFD beyond the first one. Probably the best use for a linked list of IFD’s is when you want to store multiple different but related images in the same file—a ‘burst’ of images from a camera, for example.
Adobe PageMaker® 6.0 TIFF Technical Notes

Take note of the highlighted text, software like Adobe Photoshop will ignore any IFD beyond the first one. Even worse, Photoshop won’t even mention there are additional IFD’s. I have used many document scanners which default to multipage TIFF capture and have lost pages because of this. Because of this I have always built my workflows around single page TIFF’s for all scanning and we check against this as a rule.

What also makes this hard is how some capture software uses additional IFD’s. CaptureOne is a popular imaging software used by photographers and cultural heritage institutions. We have used it to connect to our PhaseOne cameras for capture of books and other flat objects. By default the software exports the final TIFF image with a thumbnail.

With the “No Thumbnail” unchecked we get this TIFF structure:

identify _MG_0193.tif 
_MG_0193.tif[0] TIFF 3456x5184 3456x5184+0+0 8-bit sRGB 51.3136MiB 0.030u 0:00.026
_MG_0193.tif[1] TIFF 107x160 107x160+0+0 8-bit sRGB 0.000u 0:00.007

 <IFD0:ImageWidth>3456</IFD0:ImageWidth>
 <IFD0:ImageHeight>5184</IFD0:ImageHeight>
 <IFD1:SubfileType>Reduced-resolution image</IFD1:SubfileType>
 <IFD1:ImageWidth>107</IFD1:ImageWidth>
 <IFD1:ImageHeight>160</IFD1:ImageHeight>
 <IFD1:BitsPerSample>8 8 8</IFD1:BitsPerSample>

So Imagemagick identifies two pages 0 and 1 with the second a much smaller resolution than the first. Exiftool reports back IFD0 and IFD1 with IFD1 having a SubfileType of a Reduced-resolution image. Makes sense, it is a thumbnail. In looking at the specifications for TIFF 6.0, I can find no mention of the word “thumbnail”, but the specification does make mention of “reduced resolution” images:

If multiple subfiles are written, the first one must be the full-resolution image. Subsequent images, such as reduced-resolution images, may be in any order in the TIFF file.

The specification also gives us this warning:

TIFF readers must be prepared for multiple images (subfiles) per TIFF file, although they are not required to do anything with images after the first one.

Scary to think about how a reader is not required to do anything, not even warn against multiple IFD’s (Subfiles).

The EXIF specifications seem to expand on this through attributes:

Attribute information can be recorded in 2 IFDs (0th IFD, 1st IFD) following the TIFF structure, including the File Header. The 0th IFD records compressed image attributes (the image itself). The 1st IFD may be used for thumbnail images.
Page 97 of EXIF Specification

Take a look at the information and Figure 6 on page 21-22 in the EXIF specification.

Adobe early on decided to use their own tags for thumbnail data. Since Photoshop 5, Adobe has stored the thumbnail in Tag 1036.

 1036 Photoshop Thumbnail             : (Binary data 4625 bytes, use -b option to extract)

There is another TIFF structure sometimes used in older FAX compressed multipage TIFFs and now used in the DNG Specification. The SubIFD tag was writable using the libtiff “thumbnail” tool, but is now depreciated. Originally described in the TIFF/EP specification, DNG files use SubIFD trees.

DNG files are often talked about in the same way TIFF files are, and many tools handle both seamlessly. One of the major differences is that DNG files switch their IFD use. IFD0 is often the reduced-resolution thumbnail and SubIFD the full-resolution image.

<IFD0:SubfileType>Reduced-resolution image</IFD0:SubfileType>
<IFD0:ImageWidth>256</IFD0:ImageWidth>
<IFD0:ImageHeight>171</IFD0:ImageHeight> 

<SubIFD:SubfileType>Full-resolution image</SubIFD:SubfileType>
<SubIFD:ImageWidth>3516</SubIFD:ImageWidth>
<SubIFD:ImageHeight>2328</SubIFD:ImageHeight>

This can cause issues when trying to extract technical metadata from images, knowing which IFD to get the main image details requires a bit of work. I’ll save DNG for another blog post.

TIFF Metadata is a vital part of preservation. The metadata can provide technical properties of the file along with some descriptive information. It amazes me how much the embedded metadata can vary from a scanner or camera capture device. The digitization lab I worked in for years had scanners from Epson, Fujitu, Canon and others. Along with cameras made by Canon, PhaseOne, and Copibooks. Each one with a vastly different set of metadata using different standards. Even when each workflow produced final uncompressed TIFF images, they all varied in metadata.

The TIFF images with the leasT amount of metadata was from the Epson scanners. When using the free Epson Scan software, not a single metadata field was embedded, no dates, scanner model or manufacturer. More was embedded when you used the Silverfast professional software included with each Epson, but even then if you didn’t add any IPTC fields, the metadata was limited.

The most metadata came from the camera systems, especially the PhaseOne/CaptureOne systems. Even though it produced the most and had valuable properties, there were some issues. I already discussed the thumbnail issue, but PhaseOne decided they wanted to change how some of the tags were used.

CaptureOne has quite the list of white balance options. Which is great for the photographer, but not so great for adhering to the TIFF standard.

According to the EXIF TIFF Specification, there are only two values allowed for White Balance, Auto or Manual. A CaptureOne produced TIFF will have this value if Auto or Manual are not chosen:

41987 White Balance                   : Unknown (5)
37384 Light Source                    : Other

The different lighting situations should be identified using the “Light Source” 37384 tag, but alas they chose to add to white balance instead. When I asked about this, they responded that they requested this update to the TIFF spec, but they weren’t willing so they took matters into their own hands. You can read the conversation on the JHOVE issues page.

The TIFF format is very accepted in the Cultural Heritage community as a preferred preservation format. The specification is well understood and documented. I just hope we can continue to openly discuss issues that arise in preservation which add risk to our collections. Some issues are minor compared to others. Sometimes it’s the tools we use to validate formats like TIFF which are wrong and need to be corrected. The talk more about these issues and how to manage them.