1993.12.15 18:17 "", by Kevin O Grover
this mail address has been forwarded to me by a default message from Sam Leffler, saying that here I can get informations about tiff. The question is: I have been informed that tiff and g3 are actually rather similar outputs; what is the best way to transform one of them into the other; I am also looking for a fast way to transform g3 or tiff into Postscript; I tried using pbmtools but unfortunately the do finish as soon as a page is longer than a certain lenght; it is also possible that this was just an error in the way the G3-Files were constructed: Two G3-Files have been linked by removing the EOP-MARKER on the first page.
You'll probably get a million replies, well, here goes another
G3 is a compressions scheme, it comes in two flavors: 1 dimensional and 2-dimensional. The G3 2D is the standard FAX compression. There is another compression called G4 (G means Group) and is really the same as G3 2D except that lines are never synchronized (they are synchronized -- i.e. 2d compression starts over -- every 4 lines in G3 2D). The G3 and G4 compressions are part of the CCITT recommendations T.4 and T.6 (I can send you more detailed citations if needed).
TIFF is wrapper specification for images. A single TIFF file can have multiple images (although that's rare). The images can be compression in any number of ways (Tags included in the image tell you things like this). Individual companies could also define their own tags.
For more information get TIFF6.ps (the TIFF 6.0 Specification) from:
And there is a library that can deal w/ tiff images (and some utilities):
If you need more detailed information, let me know.
- kevin, firstname.lastname@example.org