Re: Gum Tri-Color Yellow

I still haven't taken time to read the rest of this thread, and
apologize to anyone who had a good point that I haven't seen yet. I did
actually go to the archives to look for the thread just now, but it had
disappeared into last month's archives and I was too lazy to follow it
there.

I was trying to stay out of here so I could get to a task that I've been
avoiding, but as often happens, when I get curious about something I
keep thinking about it until I can find some resolution or until I
realize that resolution is unlikely. So instead of working on my other
project, I've been spending more time than I should, (1) trying,
unsuccessfully so far, to print a color balance I like using PV19 and
various yellows and cyan-like colors, and (2) studying about reflectance
curves and cone sensitivity profiles and saturation costs and stuff
until my head hurts.

The problem as I see it is that while printing inks come in "magenta"
"yellow" and "cyan" our pigments don't come labeled that way, and in
some cases it's questionable whether the pigments we choose are a good
match for the process colors. In my case, the colors I print tricolor
with are definitely not a good match for the process colors, and I've
never intended or presented them to be. I just like the rich clear
luminous color mixes they print in combination with each other.

What I've been trying to figure out the last couple of days is why the
colors I use, which are so off from process colors in various ways and
amounts, give the result they do in combination, and I've finally
decided I can't figure it out and it doesn't matter. It seems more and
more complicated the more I get into it, and when I came to the part in
some resource where it said that reflectance graphs don't necessarily
tell you how pigments will mix, since very different pigments with
different chemical properties will give similar reflectance curves, I
gave up and decided this is just going to be one of those unknowable
things as far as I'm concerned.

But back to PV19: in studying the reflectance graphs of PV19 (gamma)
against the reflectance graph of an ideal process magenta ink, it seems
clear that the secondary peak of PV19 is shifted well into the violet
region (between 400 and 425) as compared to the secondary peak of
process magenta, which is more at the boundary between violet and blue
(450 or higher). So I still think that if you're looking for a pigment
that will match process magenta, this may not be the best pigment. But,
again as I've always said, each to his own; if you've found a way to
make it work for you, use it in peace.
Katharine Thayer
Received on Fri Jul 2 14:46:48 2004