[Tig] Red channel missing

Bob Friesenhahn bfriesen at simple.dallas.tx.us
Tue Oct 28 18:49:10 GMT 2008


On Tue, 28 Oct 2008, Bob Friesenhahn wrote:
>
> This would be a good time to explore the wonders of black/white.  Set the red 
> channel to a constant value (I recommend 0.2126 of max range if this is sRGB 
> or Rec.709, or 0.299 if it is Rec.601 video) and then convert to grayscale. 
> Then adjust contrast to suit.

Special purpose software could estimate a red channel based on the 
individual pixel values which achieve a median black/white intensity 
level.  For example, if you had an image of an 18% gray card, then it 
should be possible to compute a red channel which provides a fairly 
nutural color balance even if colors are not accurate.

Bob
======================================
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/





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