DPX log image?

Robin,

Do you have a DPX or Cineon log image you can provide to me or know 
how I can accurately produce one?

I am a bit concerned in that the documented procedure for producing 
linear RGB from log RGB is a one-way trip.  The procedure clips the 
dynamic range so that the image looks right on a normal 8 bit display. 
If this procedure is used to convert to a 16-bit image, the same 
clipping would be applied.

There is a procedure for how to produce log data from an 8-bit image, 
but of course in this case the dynamic range has already been clipped.

I don't like the idea of GraphicsMagick damaging the image just by 
touching it.  I am thinking about creating a CineonLog "colorspace" so 
that log images would be read in without translation (except if the 
GraphicsMagick build can only support 8-bits per sample).  This would 
at least allow performing some operations which don't care about color 
(e.g. rotation, scaling, cropping, and maybe even some filtering) 
without additional damage (in terms of dynamic range) to the image. 
If the result was again saved using log data, there wouldn't be any 
damage.

The papers at http://www.digitalpraxis.net/ discuss linear vs log a 
bit.

Bob
======================================
Bob Friesenhahn
[email protected], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/


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