AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2004.12.07 12:25 "[Tiff] Fetching pixel data from 4bit tiff", by Dan Field
2004.12.07 11:32 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Joris
2004.12.07 12:38 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Dan Field
2004.12.07 11:48 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Joris
2004.12.07 12:57 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Dan Field
2004.12.07 12:21 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Joris
2004.12.07 13:02 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Joris
2004.12.07 15:50 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Dan Field
2004.12.07 15:52 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Bob Friesenhahn
2004.12.07 17:46 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Dan Field
2004.12.07 17:04 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Bob Friesenhahn
2004.12.07 20:00 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Joris
2004.12.07 20:41 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Bob Friesenhahn

2004.12.07 11:48 "Re: [Tiff] Fetching pixel data from 4bit tiff", by Joris

Ah, excelent. I was starting to doubt my data. So if it converts from greyscale to RGBA, surely the R, G, B values would all be the same? eg

R=45
G=45
B=45

The data I'm pulling out doesn't fit this pattern at all:

eg:

R       G        B

71      202     94
14      209     94
213     215     94
156     222     94
99      229     94

I'm not using the stuff myself, but it should indeed return R=G=B if the source is indeed grayscale. Perhaps we can see what's going on if you post a tagdump of the source tiff, and a code snippet. (A tagdump can be made with a tool included in LibTiff, tiffinfo, or by the tag viewer pointed to in my signature if you're a windows user.)

Joris Van Damme
info@awaresystems.be
http://www.awaresystems.be

Download your free TIFF tag viewer for windows here: http://www.awaresystems.be/imaging/tiff/astifftagviewer.html