Re: [GM-help] How to convert DPX from RGB to grayscale but in log?
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From: Bob F. <bfr...@si...> - 2013-09-08 14:46:13
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On Sun, 8 Sep 2013, Joakim Ziegler wrote: > I found the -define dpx:colorspace=rgb option, which should let me read > Cineon encoded files as what you call linear (really a G2.2 or some > such, I assume), and which should give me the same curve when writing > grayscale out, however, while this gives different results, the > resulting grayscale DPX file is still considerably more contrasty and > clipped than the original RGB file. I think that doing gm convert infile.dpx -channel green outfile.dpx should be sufficient and it avoids any conversion from RGB to grayscale. However, please note that there is a long-standing bug in GM in that it fails to deal properly with 10-bit gray DPX images unless their width is evenly divisible by three. 8, 12, and 16-bit depths do not suffer from this problem. Sorry for the problems. GraphicsMagick is not originally developed to deal with log images and it is easy to break other normal behaviors by improving behavior for log images. Bob -- Bob Friesenhahn bfr...@si..., http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ |