Re: fabriano paper

On Thu, 6 May 2004, Christina Z. Anderson wrote:

> Now THAT'S the question to ask. I know there are such things as:
> alkyletene dimer or aquapel, whatever the heck that is. You chemists can
> tell us laypersons.

I found Aquapel impossible to use as a hardener applied after a gelatin
coat. Even a 1/2 percent solution left a surface so impervious that gum
emulsion simply balled up on it -- no way to apply a coat that would grip.
Then the next lower solution (as I recall 1/4%) had no hardening effect at
all --- illustrating what I suppose could be called a very steep curve...
(I didn't try putting it *in* the gelatin.) I also gather that papers
manufactured with this material as size use it internally, not as a top
coat.

I suspect, BTW, that this is the reason use of both alum and formaldehyde
for hardening persisted 100 years -- it wasn't lack of imagination, or
unavailability (I've had Aquapel on my shelf probably 30 years & suppose
it was around before that.) It was because they worked.

> > Do you see any relation between degree of shrinking and sizing?
>
> Another interesting question: paper supposedly shrinks 15% when first wetted
> and dried. Don't know where I came up with that information, so it could be
> incorrect. Anyway, watercolorists will wet the paper and tape it to a board
> (or staple it, as I do) and it'll dry drum tight. I was thinking this very
> thing as I was preshrinking this paper, because the feel of it is that the
> sizing is...something new, or acrylicy or something. I can't describe it,
> except that the sizing feels substantial. So I was wondering how much
> shrinkage would occur with a paper that has such a hefty, stable, size and
> one that may be synthetic like an acrylic. And therefore, whether I really
> needed to do this preshrinking step, which is a pain when you are doing 100
> sheets of it (which I did).

It's possible that your gelatin sizing and hardening do your entire
shrink. But the only way to know for sure is to test -- size and harden a
piece of paper. Measure the longest dimension. Then coat it with
something, dry, expose, and develop for however long you develop. Dry
again. Then measure again.

This CANNOT be determined "theoretically".... except by coincidence.

Judy

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Received on Thu May 6 14:12:32 2004