Oh yes... and I've been around long enough to see the bright-eyed graduate
students interviewing the old timers, who give their doctored version of
events with themselves at the center (if everyone who says they were in
"the club" was -- they would have had to meet in Madison Sq Garden)... And
then the interviews get written into history...
But I got caught myself recently... repeated something I'd heard as truth,
and now a couple of fellas say I should have known better. So I should.
> And gum printing is a process that lends itself to each practitioner
> finding their own way - but it's hard to explain to others because often,
> much of it is intuitive. I think too that with gum printing, much of the
> knowledge is built through the phyiscal process of gum printing - and the
> "feel" of materials guides you in how you approach the craft.
Exactly -- and making the print is *interactive*, like painting. That is,
you look at what's happening and decide what to do (or try) next. I think
that may be one reason platinum printers (among others) can have trouble
with it. They're accustomed to everything determined in advance, a
detailed protocol.
>....I think that staining is not something necessarily caused by
> pigment to gum ratio alone. You also have to take into account how many
> printings the length of exposure and so on. What I do know is that
> staining
In my experience, staining is not related to pigment-gum ratio at all,
except maybe if you're getting staining, you might have proportionately
more if you have proportionately more pigment. But I've made tests where
I DOUBLED the pigment, got it so concentrated it looked straight from the
tube, and it didn't stain.
> ususally is more a problem after 9 or 10 coatings than the first... Plus
> too
> much exposure.
Some people will add another coat of gelatin just to be on safe side when
they get to so many coats. Have you ever tried that?
> Plus you would need to test each batch of
> gum also. Some are thicker than others, though from what I can ascertain,
> a
> thinner gum doesn't necessarily lead to more staining.
I took 3 gums that behaved very differently, one *seemed* much more
viscous than the others, to school and tested with the hygrometer. All
measured the same 13 baume (tho all were nominal 14 baume). They had very
different speeds and printed differently, so I can only assume those
differences are chemical, which side of the slope the acacia tree was
growing on, what preservative, etc....
>.... I know for
> instance that cad yellow stains easily, and needs less pigment to gum
> ratio. cad red and alzarian crimson are well behaved, rarely staining,
> even with copious amounts of pigment to gum. Ultramarine and prussian
> blue tend to be the worst, as others have indicated. Browns and viridian
Hamish, in my experience that's according to the brand... For instance,
W-N ultramarine stained badly. Rowney not at all.
> On the question of the printing out image in gum. Browns yellows reds
> viridian - you can judge pretty accurately, forget about blue, and after
> the second coating.... I read recently that different colours also affect
But also thickness of coat is a factor... I tend to put on the thickest
coat possible at least for the first and in a dark color that doesn't show
a printed-out image, at least not in this house...
But I'm curious what you use the cadmium yellow for??? Are you doing
tricolor?
> each little extra idea extends what is possible. The definite book on gum
> printing would be hard to produce, because different techniques are driven
> by the desire to produce a specific finished result. Trying to explain all
> of this logically is difficult - its better to show people..
But the mystery part of the allure, n'est-ce pas?
Judy