RE: "speckling" v "staining "

On Sat, 10 Sep 2005, Don Bryant wrote:

> From the very first tests I did with glyoxal, I found it hardened better
> than formaldehyde
>>
>
> How did you determine that glyoxal hardened better than formaldehyde?

I took identically sized paper and hardened one batch as usual in
formaldehyde (outdoors), the other batch in glyoxal (outdoors), dried both
fully (outdoors) and the following day exposed a couple of my standard
emulsions in standard manner under blacklights standard time, developed
standard manner.

The glyoxal hardened paper cleared pure paper white (I remember that
because it was so dramatic, though I'd have to ransack milk carton of
tests in folders to find actual strips & number of steps -- probably
the same on both.)

The formaldehyde hardened paper showed definite stain in the whites. And
also that paper was still, a day later, outgassing so strongly it hurt
my throat & made my eyes burn -- until I took the extra sheets out of the
studio.

It occurred to me later that the formaldehyded paper might simply have
taken longer to "mature' -- that after the outgassing was finished, maybe
a day or two later, it might have also cleared paper white... But that
wasn't the point. The point was to see if glyoxal hardened as well. It
did, while being much easier to use and to get.

But Don, I read your rundown on practice, which seems essentially like
mine except for the dremel stirring... I was waiting for some different
finding -- Or disagreement... ????

>> 4. another thought about speckles -- I do NOT NOT NOT mix paint with gum
> and keep in a jar for later use. IME the paint settles at the bottom and
> is very difficult to remix smoothly.

> I've discovered a way to ensure that the pigment and gum are mixed
> thoroughly every time. I use a dremel tool with a cone shaped brush
> attachment to blend the mix to a homogeneous creamy puree prior to coating.

That's STILL something I don't understand -- it seems like a lot of
trouble and no gain. I mean I usually want to adjust a mix anyway, color
and/or amount, and although the dremel is ingenious -- um I dunno,
couldn't you electrocute yourself? And isn't it still a drag to clean???

Somebody else, as I recall, said thalo blue doesn't clear. My finding is
that some *makes* of thalo are difficult, not the pigment itself. As so
often the case, it's probably the additives, not the color... In any
event, Daniel Smith and (I think it was Rowney I'd have to check) are
fine. In fact I use thalo blue as benchmark for tests as well as "process"
blue, or cyan.

Judy
Received on Mon Sep 12 21:50:59 2005