Re: "speckling" v "staining " (was New Orleans/glut) SEE SCANS

Ender100@aol.com wrote:
>

> Katharine Thayer wrote:
> Certainly, but my point was that in my printing on
> glyoxal-sized papers,
> the tiny numbers and letters at the top of the Stouffer
> 21-step, which
> are probably smaller than the numbers on your wedge, print
> perfectly
> white and sharp and legible, and this is true even on BFK,
> so I don't
> think it's the limitations of gum that makes the difference.
> But yes, it
> could be something about the difference in lights.
>
> *  I compared the size of the numbersâ*”the numbers on the Stouffer 21
> are about 50% larger than on my (PDN) 31 step wedge, so refraction of
> the light would be a bigger factor. 

Are you telling me that the number T2115 on the top of the Stouffer
21-step is 50% bigger than numbers on your step wedge? If so, those
numbers are very small indeed. It's the T2115 I was talking about, when
I said it prints absolutely sharp and clear on gum, in response to your
suggestion that gum itself is incapable of making small distinctions.

Fog, of
> course.    But what
> would cause the fog then, would be my question. The lights?
> Or the
> sizing? Or what?
>
> *  I have no idea what might cause the slight fogâ*”I would suspect
> some low level of exposure first prior to exposure. 

Well, maybe, but since I coat and dry in daylight, I find it hard to
believe, unless you really took a long time to get your paper ready to
expose. And the very dilute dichromate would argue against that, too.

 I don't think the
> dichromate gum mixture would suffer from "chemical fog".

Of course not; if so, I and other gum printers would have noticed this a
long time ago.

  I would not
> know what other issues could cause itâ*”chemicals in the paperâ*

I doubt that too, since I've printed on that paper without fog, unless
it's some kind of a reaction between the paper's internal sizing and the
glutaraldehyde, or something like that.

My question wasn't meant as a direct question that I expected you to
come up with an answer to, it was a rhetorical question directed to the
group at large. Seems to me Joe reported some test results suggesting
that some fluorescent lights fog gum. Since I've never used tubes, I
wouldn't have any information to add to that, but that might be a place
to look.

>
> My guess is that fog is a different phenomenon
> > than stain, or is it? 
>
> Certainly, yes Stain has nothing to do with exposure; if
> stain is going
> to happen it will happen whether the coating is exposed or
> not. Stain is
> when the pigment penetrates the paper and colors it
> permanently. Once
> the coating is brushed on the paper, the stain is already
> there. This is
> also true of the two kinds of speckles that I have
> described.
>
> * That makes sense.  Perhaps this is part of a definition that could
> be used for stain.

Well, it certainly is an intrinsic component of the definition I have
used for years and argued here many times.

Katharine
Received on Fri Sep 16 09:18:30 2005