2004.03.26 16:00 "Re: [Tiff] Jpeg compression of grayscale images seems odd", by Andrey Kiselev
I have recently sync'd back up with CVS and it seems that the jpeg compression seems broke in the HEAD tag, 3.5.7 works fine though. When I compress a grayscale tiff file using JPEG compression, it seems that the image has reversed the black and white bits. As if the TIFFTAG_MINISBLACK and TIFFTAG_MINISWHITE are reversed. Here is what I do? Scan an image using TWAIN and Irfanview. (fine) Load the file using Imaging for Windows NT (fine) Use tiffcp thusly ( tiffcp -c jpeg:r scan.tif small.tif ) (fine) If I look at the file using Irfanview the image has reversed polarity and... If I then use tiffcp thusly ( tiffcp -c none small.tif newOriginal.tif ) and try and load newOriginal.tif in Imaging for Windows NT it gives an error.
It seems that I have fixed the problem with Photometric Interpretation today (along with the couple oth other bugs, now Windows build should run smoothly). Please, try the latest snapshot.
BTW, I'm not sure that Imaging supports JPEG compressed TIFFs.
Andrey V. Kiselev
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