Digital BW, The Print

> > It may not be the "same thing" but you certainly can get the EXACT same
> > results in your final grayscale output.  You can do manipulation to the
> > grayscale data and arrive at the EXACT same resultant output as
> you can by
> > manipulating the RGB data then converting to grayscale.
>
> Let say there's a grayscale image of an 18% blue patch, an 18% red patch,
> and a greyscale strip.
>
> With the channel mixer and an RGB image, I can alter the tonal
> values of the
> blue and red patches, making one darker and lighter without affecting any
> changes on the tonal values of the greyscale strip.
>
> In a greyscale image, the colour patches appear identical, both
> middle grey.
> I can manipulate the greyscale data, but it makes no distinction
> between the
> red and blue patches because they are both the same grey value.
> If I change
> the value of one colour patch, the value of the other colour patch is also
> changed in the same manner, as well as the corresponding grey patch on the
> greyscale.
>
> How can you manipulate the greyscale image to separate or blend different
> colour values as you would via the channel mixer, if there are (obviously)
> no colour values in the greyscale image?

Moreno,

If the original image is real color data, not B&W scanned as RGB, yes.
Doing as you suggest to a B&W image scanned in RGB doesn't work.

But that begs the question, why?  If you are drastically altering the
reality of the tonality, that more becomes art than photography, at least in
my book.

Austin