U of S | Mailing List Archive | alt-photo-process-l | Re: my pigment dilutions

Re: my pigment dilutions

Sorry, Loris, I'm not understanding what you're doing here at all, or
more accurately, I think I understand what you're doing, but not what
you think you're learning by it.

If I'm understanding correctly, it looks like what you've done here
is squeeze paint out of tubes in an attempt to mix black from three

It's not necessary to use three colors to create black with paint.
Painters mix black all the time with two colors; handprint has a
whole page listing pairs of complementary colors that mix to neutral

Three colors are even easier to mix to black; a wide variety of
combinations of three colors will mix to black right out of the tube,
or even at tricolor concentrations. Since these three pigments are
approximately equidistant on the color wheel, one would expect them
to mix to black, as explained by handprint, so it's hardly a great
surprise that they do.

Whether the pigments add to black is a question of their hue and
where their hues stand in relation to each other on the color wheel;
the question of whether the yellow can hold its own with the other
pigments isn't so much about whether it can add to black, but how it
mixes with the other colors to form secondary and tertiary colors,
and how the greys look, and while that does depend partly on hue,
it's also dependent on pigment strength, value, and other variables.
It's the value (lightness) and pigment strength of PY 151 that makes
me say that for the kind of printing I do, I don't feel that it holds
its own with other colors at the concentrations I like to use them.
But that's just me; I'm not trying to talk you out of using it. All
I was saying is that PY 151 is very different from PY175, so it might
not be useful to go by Chris's proportions. That's all.

I thought you were going to calibrate your three pigments at
tricolor concentrations, then print overlaid step prints and see if
that gives you neutral greys and blacks. That would tell you
something about the neutral balance of the pigments in the relevant
concentration ranges, but not so much about the color palette; you
have to print colors for that. (Yes, the two variables overlap, but
they aren't identical). But what you've done here doesn't tell me
much of anything at all, sorry.

Being an old-fashioned gal who was printing tricolor a long time
before it got so gol-darn complicated, I'd personally recommend just
throwing caution to the winds and printing tricolor. Most people who
just print tricolor without all the calibrating and testing and
fussing and esoterica find that it doesn't take more than two or
three tries to get it right (I got the right combination on my second
try) and then you can just print. But, each to his own.

On Oct 25, 2008, at 3:50 PM, Loris Medici wrote:

Katharine, see below:

25 Ekim 2008, Cumartesi, 10:15 pm tarihinde, Katharine Thayer

Dear All,
At this URL I posted a visual of my pigment dilutions:


Thanks for that, that's helpful. Will analyze more deeply (by
our yellows) but at first sight it seems that both of the my planned
magenta and pthalo concentrations are considerably stronger (in
to yellow) than yours.

I think this may have more to do with pigment choice than
concentrations, Loris.   The PY 151 is a very light pigment; to my
mind it simply can't hold its own with most magentas and cyans and
for that reason I don't recommend it for tricolor but prefer yellows
with a little more oomph to them.

I've just made a test (albeit a clumsy one):

I mixed 2.5 to 3 part PY151 + 1 part PV19 Rose + 1 part PB15:3 over a
sheet of Yupo. I didn't measure exactly, just eyeballing the
squeezed out
paint amnts. Hence the designation "clumsy", and the uncertain
of Yellow.

See the result below:


The black section above is a fully exposed and developed glossy RC
that I use as reference black in scanning (log 2.0 or slightly more
density). Below this, you can see a patch made by mixing paints. I
averaged inside the white square and the color sampler says it's
R17 G15
B13 (L2 a1 b1 in Lab mode) relative to Dmax of a glossy RC S/G
print. From
this I understand Y > M > C; Yellow is pulling both Green and Red
Up, and
since Blue is less than Green that means Cyan is weaker than
Magenta (if
not, then Blue would be stronger than Green). Correct me if I'm wrong
please - because all this color stuff is still new to me. Anyway,
this is
quite convincing black (both in terms of density and neutrality),
you agree? In the light of this, can we say PY151 can hold its own
PV19 Rose and PB15:3, or should I test it using a different method?