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Re: pigments for gum
On Mon, 27 Mar 2000, Andre Fuhrmann wrote:
> But Judy, you must know perfectly well that some pigments are less suitable
> for gum printing than others. Technically, because the more suitable
> pigments allow you to build up good densities with only a few printings and
> no staining problems.
I don't, alas, know very much perfectly well, or at least not in gum
printing ... the only really *unsuitable* pigments by name are those with
very little covering power, like terre verte -- but if you look at the
label, those aren't sold any more, or not widely. There's "terre verte
*shade*" which is a mix with more strength.
And as I have reported previously, the NAME of the color is no guide to
staining. For instance, Rowney ultramarine was a heavy stainer & Winsor
Newton ultramarine was a perfect printer (or vice versa, I forget now) --
and the staining ALSO varies with gum and paper -- as we discussed on the
list some years ago. Which is to say, some colors stain in some gums, not
in others. If you come visit, I'll pull out the test sheets...
Then the STRONGEST color in my paintbox is indigo -- but I don't use that
a lot if I'm trying to be good, because so little of it colors so strongly
I can't use enough to measure accurately on my scale (O'haus triple beam
balance) and my most brilliant results will be even harder than usual to
repeat. I guess you could mix up a whole batch in gum & measure by drops,
but that has never worked well for me.
> ...In short: with such pigments you get nicely
> contrasty prints with clear highlights ... if it is that what you want.
> Here we get to the aesthetic aspect. Of course, everyone is at liberty to
> use whatever pigments he or she likes. To my taste, however, tricolor
> printing is an aberration -- at least if you are aiming at "natural"
> colours. There are better ways of achieving this. But, to repeat, this
Please please let us in on it ... I for one need better for everything...
(or almost everything).
> is a matter of taste. We don't need to agree on this. But can't we agree
> on this: there is a large array of pigments, eminently suitable for gum
> printing which are, for all we know, not ill-affected by alum? And, for
I believe I believe... just which ones might they happen to be, and who is
going to tell us ???????? (Where is that PhD when you need her?)
> all I know, even with the colours you prefer for tricolor printing, chances
> are not too bad that they emerge unharmed from an alum bath.
> BTW I prefer _not_ using alum for clearing: simply because it takes too
> long and extends the final wash. I prefer using metabisulfite.
Right, me too...
Judy