Re: Gum Tri-Color Yellow

I've found time for a few more tests, but not enough for any more
completed pieces.

I've given up "just fixing the curve" in order to get the magenta PV19
to work (along with my classic cyanotype and yellow PY110). These are
not process inks, and the odd brown inter-reaction doesn't follow
process color rules :-(

I've started working with M. Graham Quinacridone Red #155 (PR209
pigment). This is a pigment suggested by Katharine a few messages ago.

First (silly) comment: who the heck came up with the name
"Quinacridone"?? I can't even say it, how did the marketing department
let that happen??

Second (silly) comment: *^&%^$ is it "red"!!

I was looking for magenta, not red. I almost didn't try it...... but I
did. The final print's color balance is far far better. My problem (and
it may be my fault) is consistency. The first print I made was too
red/orange, I tweaked the curve very slightly and the next print had
FAR FAR too green (too little magenta). Probably my fault in mixing.
I'm not looking for repeatable perfection, just a happy average that
will sometimes be "just right" after 3 coats and other times need
"another light coat" to reach "just right".

More latter, thanks again for the help.

On Friday, July 2, 2004, at 06:50 AM, Katharine Thayer wrote:

> 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
>
>
--------------
Tom Ferguson
http://www.ferguson-photo-design.com
Received on Fri Jul 2 16:03:45 2004