Digital BW, The Print

Sarah

Thanks.  I guess I get the notion of, say, 50% red, 25% blue, 25% green.
The luminance stays the same and we are choosing the weighting of RGB.  But
what about a channel value greater than a 100% or negative channel values?

Steve


> From: jessupsa <sjessup@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Thu, 17 Feb 2005 17:25:21 -0000
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: [Digital BW] Re: Understanding channel mixer
> 
> 
> 
> Steve,
> The sum of rgb adding to 100% just preserves the luminence of the orignal. You
> don't 
> have to stick with that if you like the effects of another sum. Red skies can
> get torn 
> up as you're only using 30% or so of the info that is recorded in the red
> pixels. It 
> often helps to add some additional info, such as from the L channel to your
> red using 
> channels as layers for a smoother outcome.
> The constant slider is described by Adobe thus: "Drag the slider or enter a
> value for 
> the Constant option. This option adjusts the grayscale value of the output
> channel. 
> Negative values add more black, and positive values add more white. A -200%
> value 
> makes the output channel completely black, and a +200% value makes the output
> channel completely white. "
> Sarah
>