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January 2007
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2007.01.31 16:39 "16bit grayscale with colormap", by Reinhard Mayr Aka Czerwinski
Hello, I deal with 16bit grayscale TIFFs. The files originate from a 12bit CCD, so the linear conversion 16bit->8bit turns my image almost black. To cope with that, I would like to add a ColorMap into the TIFF. For testing, I altered an existing 16bit file: o photometrics = 3 (ColorMap) o added a colormap (tag 0140), length: 3*2^16= 196608 bytes Porgrams either refuse this file (ImageMagick viewer) or ignore the colormap and treat as if without (ImageJ). Is this a proper interpretation of the TIFF specs (TIFF6 specs p.23 allow only 4/8 bits per sample -- why?)? How can I work with the data in terms of leaving original values untouched and just change a LUT/ColorMap/whatever? Thanks for all advices, hints & pointers! Cz. -- Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer