Re: Image formation in gum

On Dec 16, 2005, at 1:59 PM, Katharine Thayer wrote:
>
> But I also think it's not just an either-or thing, it's probably a
> continuum, so there are probably intermediary steps where there is
> some gum involved. I don't know, I'm just guessing.
>

I'm glad I said this last, because I've just encountered an example of
something that probably fits this in-between category. It's lamp black
on glass, where some of the hardened gum came off. It doesn't represent
a tonal inversion kind of deal; the letters didn't print in black, for
example. there is a definite pigment stain left behind where the
hardened pigment floated off, but in this case, the pigment tone is
very definitely not removable. If you look closely you can see a couple
of places where I scratched it with a fingernail, but it's definitely
not easily wipable like the pigment I was wiping off yesterday where
there was a definite tonal inversion effect. (One possible confound
is that this is on etched glass while the ones I did yesterday were on
plain window glass). But at any rate, I think this is probably an
example showing that this phenomenon is a continuum, but whether or how
the gum is or is not involved in this case, I'm at a loss to guess. It
seems to me that there isnt any gum there, but then why? as Tom said
yesterday about something else. I think this is fascinating, but
difficult to fully explain in all its possible variations.
Katharine
Received on Sat Dec 17 12:26:04 2005