[Gimp-developer] lgm talk, part 2...

[Chris Mohler]

On Sat, Jun 20, 2009 at 12:07 PM, yahvuu<yahvuu at gmail.com> wrote:
> hi,
>
> Chris Mohler schrieb:
>> On Sat, Jun 20, 2009 at 11:27 AM, yahvuu<yahvuu at gmail.com> wrote:
>>> i assume the temporary layers are mostly grayscale?
>>
>> Usually RGB layers, or grayscale channels.
>
> sorry, imprecise question. I mean, if you use a temporary RGB layer,
> it's content will still usually be just grayscale, effectively used
> as a mask. Assumed correctly?

Not necessarily - consider another scenario: mixing two spot colors to
create a third color.  More accurately, consider an image (RGB) that
is primarily three colors, and then attempting to print that image in
two colors, getting as close to the original RGB artwork as possible
(the number of spot colors is a major factor in printing cost).

In that scenario, I may end up duplicating the original RGB artwork
several times before getting the selection that I want - then
ultimately filling or erasing that selection on the spot channel(s).
The process can be very non-intuitive at times, and sometimes you just
have to dive in and do some trial and error - esp. if the original RGB
image is something flat that was not originally intended to be printed
in such a way or is "damaged" (eg, not on layers, suffers from JPEG
compression, etc.).

Chris