Re: "Speckles" on BFK [was "speckling" v "staining

Judy Seigel wrote:
>

> And finally, about yellowing from glyoxal -- There seems so far to have
> been no case of glyoxal yellowing (except at a bottom drip) when the paper
> is rinsed after a glyoxal *bath* rather than glyoxal added to the gelatin.
>
> Is this correct?

I don't know, but I haven't seen any yellowing when the glyoxal was
added to the gelatin and then the paper was rinsed, either.

I also believe that yellowing may be very paper-dependent. For example,
back early in February I sized four pieces of glyoxal-treated Fabriano
Artistico Extra White: two at .6% glyoxal and two at 1% glyoxal. One of
each pair was rinsed after sizing, one wasn't. I put these in a drawer
and rotate them every now and then so different ones spend time on top
of the stack. Seven months later, all four of these sheets are still
pure white. On the basis of my observations a few weeks into that test,
I didn't bother to rinse my second batch of glyoxal-sized Arches Bright
White, although I had rinsed the first batch. The unrinsed Arches
yellowed (the color is actually ivory, not yellow) within a day or so,
but I found that the ivoried paper turns pristine white again in the
water development that's part of the gum process, so to me the yellowing
isn't an issue; the rinse works, at least for me on this paper, whether
done immediately or weeks later as part of the gum process.
Katharine
Received on Sun Sep 4 21:27:48 2005