TIFF and LibTiff Mail List Archive


2004.12.15 04:30 "[Tiff] Q: Fax photometric", by Chris Losinger
2004.12.18 17:44 "Re: [Tiff] Q: Fax photometric", by Bob Friesenhahn
2004.12.18 18:40 "Re: [Tiff] Q: Fax photometric", by Joris
2004.12.18 20:58 "RE: [Tiff] Q: Fax photometric", by Bill Bither
2004.12.18 23:13 "Re: [Tiff] Q: Fax photometric", by Joris
2004.12.18 21:24 "Re: [Tiff] Q: Fax photometric", by Bob Friesenhahn
2004.12.20 13:34 "Re: [Tiff] configuring for JBIG", by Leonard Rosenthol

2004.12.18 20:58 "RE: [Tiff] Q: Fax photometric", by Bill Bither

The question I have about this image is why does photoshop and some others read it "incorrectly" according to the spec but visually correct? Is the assumption that any CCIT RLE (1D) image that has PHOTOMETRIC_MINISBLACK actually encoded as "Min as White"? Or only with images encoded from this particular vendor (skyline tools)?


Bill Bither

-----Original Message-----

From: [] On Behalf Of Joris Sent: Saturday, December 18, 2004 1:40 PM To: Bob Friesenhahn; Chris Losinger

They may do this because some TIFF files are created with the wrong setting and users complain.

They may do this because 'it seems that these popular applications always assume the normal case'.

Food for thought, I think. Your universal reasoning 'it's not a bug, it's a compatibility feature', consistently results in propagating the bug. In the end, we'll need a specification and an extensive bug list overriding that specification in order to ensure data exchange. Unfortunately, some will consider the spec the actual specification, and ignore your bug list. This way, your 'compatibility feature' reasoning results in incompatible codecs, and lots of data that one or the other considers corrupted.

This is why most think bug compensation can be a good thing in readers only, if at all possible, but no writer should ever be made to write in buggy ways for 'compatibility' reasons.

Furthermore, your reasoning 'we should keep the bug because users might complain', whenever posted in this list, is consistently the answer to at least one user complaining about the bug, instead.

Chris, I believe you should make an entry in the bugzilla interface. I will first check CVS, and, if still necessary, do the same for the IPTC tag datatype bug, when I get around to it.

Download your free TIFF tag viewer for windows here: