Re: gum printing color combinations

On Dec 21, 2005, at 4:43 PM, Christina Z. Anderson wrote:

>
>
> BTW what the heck is the difference between semi-opaque and
> semi-transparent? Is it like the difference between partly cloudy and
> partly sunny? Anyone have a clue?
>

It's just a way of attempting to break a continuum into separate
categories. Creating four categories allows one to make a distinction
between semi-transparent and semi-opaque, but since different raters
put different pigments in those categories, there's no clearly
agreed-upon distinction between the categories. There's no reason you
can't assign pigments into your own 3-point scale: transparent,
opaque, and somewhere in between, if you want to. In my own personal
rating system, and I think in most rating systems, semi-opaque is more
opaque than semi-transparent is. Take yellows, for example, I'd say
that the most opaque yellow is PY 184, bismuth vanadate. That pigment,
I would call opaque, as Daniel Smith does. But Daniel Smith calls the
cadmium yellows semi-transparent, which I would not agree with at all.
I would call the cadmiums semi-opaque at most. They are definitely
more opaque than PY 97, which I would call semi-transparent, which is
more opaque than PY110, which I would call transparent. To me, these
four categories are useful, but it just depends on how fine you want to
draw your distinctions, and that's purely a personal preference.

It's like the question of which pigments "work" for tricolor, as far as
making a print that looks like a color print. Sure, nearly every
combination of a red, blue and yellow will produce a print that looks
like a color print: things that should be green are green, things that
should be purple are purple, and so forth. But there are dozens of
different greens, and dozens of different purples, and the greens and
purples that are produced by one set of pigments will be different from
the greens and purples produced by a different set of pigments.
Whether that's important to any particular gum printer is, again, a
purely personal preference, but I think it's useful to know the
different "palettes" using Mark's name for it (which I like), that are
produced by the different combinations of pigments, and am looking
forward to seeing your samples when you get them uploaded. If they
look like what I've got so far, I may just link to yours rather than to
finish creating my own; I'm determined to spend less time on gum
printing this year and more time writing. If I decide to do that, I'll
ask permission before linking.

Yes, it's quiet. I'm not shopping, but I'm cleaning house, or more
accurately, finding ways to avoid cleaning house, and dealing with a
leak in the dining room which threatens to bring down rain, if not the
ceiling itself, on the Christmas dinner.
Katharine
Received on Wed Dec 21 19:43:27 2005