The TIFF versus JPG debate
THX1138 at dakotacom.net
Tue Aug 15 11:24:24 CDT 2006
Armistead, Jason wrote:
> My $0.02 worth on the abovementioned subject:
> TIFF has lots of ways data can be encoded within the basic TIFF file
> structure, including LZW, CCITT G3 and CCITT G4 formats. If anyone is
> interested, get a good look at the TIFF V6 specification, although the links
> on the www.libtiff.org site seem to be broken and Adobe has now put their
> copy of the TIFF specification behind a whole lot of "developer registration
> required" pages you need to get through first.
> See also http://www.awaresystems.be/imaging/tiff/tifftags/compression.html
> which describes the TIFF tags relating to compression of image data.
I've had good results with TIFF in documents that I have prepared
(user manuals, etc.). *But*, you can't stray too far from what
is "expected". E.g., don't use weird BITS_PER_PIXEL values
and expect many decoders to be able to handle your files! :-(
Also, I have found that many *encoders* fail to sort the tags
properly so when designing decoders, *expect* this problem :-/
> From where I sit, we've used TIFF with CCITT G42D (fax) compression on
> bitonal (black and white only) image documents for 150,000 engineering
> drawings with excellent results. This is a totally lossless compression
> format (what you get back is exactly what you put in) specifically designed
> to do a good job with what you'd find on pages of drawings or of text. If
> you don't need colour or greyscale, then CCITT G42D is hard to beat.
> Within the US military, the CALS (Computer-aided Acquisition and Logistics
> Support) Type 1 specification for bitonal images basically wraps the
> compressed CCITT G42D data inside a slightly different wrapper to TIFF -
> CALS is a fixed length text header, and TIFF is a lot of binary stuff. It's
> easy to convert between the two formats when you know how.
> What I like about TIFF coupled with CCITT G42D compression most is (a) it's
> lossless, (b) supports multi-page documents, (c) it's an open specification
> with (d) an open source library to manipulate the files (LIBTIFF) and (e) it
> is widely supported with hundreds of viewers available (on Windows, the free
> Imaging component works fine for most people). I can also easily transform
> my TIFF data into Postscript (btw Level 2 Postscript more or less supports
> CCITT G42D compression too), PCL or even into PDF with not too much drama.
> In comparison, PDF is locked in more or less to Adobe's Acrobat Reader (yes,
> I know there's always Ghostscript / GSView and friends ! ), and not as easy
> to manipulate - I call it more of a nearly "final form" document format than
I thought PDF's could just be used to *encapsulate* regular TIFF's?
I.e., in much the same way that they can encapsulate JPEGs, etc.
> JPEG is not suitable because it was a lossy format targeted at colour images
> more than black and white, and it wasn't multi-page. I believe the JPEG
> 2000 specification has improved on some of these such as providing a
> lossless compression option, and can handle multi pages. I don't know if
> software to support all these features is (a) cheap or (b) available.
> For my money, I'm sticking with TIFF
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