Re: Image formation in gum

I forgot the URL. Here it is, the possible in-between example:

http://www.pacifier.com/~kthayer/html/glasstain.html

On Dec 17, 2005, at 10:25 AM, Katharine Thayer wrote:

>
> 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 12:30:41 2005