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

Hmm. I hate to confuse the issue further, but I'm not sure I mean the
same thing as either of you by the terms "speckling" and "staining."
(Man, in 150 years, don't you think gum printers could at least have
come to agree on some basic terms? But I digress.)

By staining, I just mean staining, in other words an overall permanent
stain of the paper by the pigment. There's an example of what I mean on
this page:

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

Speckling, I suppose, could be considered a form of staining, because
it's a permanent stain, but to me it's a different thing than an overall
pigment stain, because it only stains places where there's a flaw or a
disruption in the internal sizing. So what I call staining and what I
call speckling spring from different origins and shouldn't be confused
with each other. Speckling is most often related, in my experience,
either to the paper itself, something about the way it's manufactured,

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

or to preshrinking in too hot water, which disrupts the internal sizing.
I don't think all papers are affected by hot water to the same extent,
but some are. Here's an example of this

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

 This is actually Chris's image, but since it has been linked to here
with permission before and the link is out there in the archives for
folks to link to any time, I hoped it would be okay to link it again.

According to Chris's description, the paper was shrunk in very hot water
but didn't get entirely wet, because (as I recall) there were a lot of
papers in the tub and the water didn't get between all the papers
equally well. It seems apparent from the image that the paper under the
right side of the image was entirely in the hot water; the speckling on
that side is what I'm talking about, not the blotching on the left side
where the water soaked in only here or there.

This same kind of speckling can be caused by sizing with the size too
hot, and by the same token I think it depends on the paper whether this
is the case or not. There was a time when I thought that it was
something about getting the gelatin too hot that caused the speckling,
but later I came to realize that it didn't have anything to do with the
gelatin;, it's just about the water that the gelatin is mixed into,
being too hot. I proved this to myself once when I was sizing papers and
reheated the size in the microwave (I think Chris's thermos idea for
keeping the size at the correct temperature is excellent) and realized
after sizing a few more papers that the thermometer had gone up to 160F.
I marked the papers that had been sized with the hot size, and cooled
the sizing down to 125 or so before finishing the sizing. Sure enough,
the papers that had been sized at 160 speckled when printed with gum,
but the papers that were sized after the gelatin was cooled, didn't
speckle. So obviously it didn't have anything to do with anything that
happened to the gelatin, but only with the interaction between hot water
and the internal sizing of the paper. I'm sure I reported this to the
group at the time.

Don doesn't say how hot his "very warm" water was for the preshrink, but
since I have seen with my own eyes several instances where hot water or
hot size affected the internal sizing enough to cause speckling, and
I've seen no instances at all with my own eyes where glyoxal caused
speckling, I'd be more inclined to suspect the hot water preshrink than
the glyoxal itself, for the resulting speckles on Don's BFK. I can't
say my experience with glyoxal is huge (I printed one piece of
glyoxal'ed Fabriano EW and one piece of glyoxal'ed Arches Aquarelle,
just to see if I could replicate Chris's results, but I got no speckles)
and I've printed maybe 20 pieces of glyoxal'ed Arches Bright White, with
nary a speckle. More to the point, it seems to me that since people have
been using glyoxal for 15 years or so, and a LOT of people have used
glyoxal-- if speckling were a big problem with glyoxal, you'd think it
would have been reported more before now.

BTW, is it true that so far, of all the gum printers on the list only
Chris and I have actually printed gum on glutaraldehyde-hardened
gelatin? Since we used different papers and different concentrations,
our results simply can't be compared. More data are definitely needed
before anyone draws any kind of conclusion about the relative merits of
glutaraldehyde vs glyoxal as hardeners for gum size.
Katharine

Judy Seigel wrote:
>
> On Fri, 2 Sep 2005, Christina Z. Anderson wrote:
>
> > The Rives speckled tremendously (Mark brought the test wedgies home with him
> > and Jane), and after a couple hours of still-developing I did spray it and
> > the stain never disappeared.
>
> You seem to be using the terms "speckling" and "stain" here as meaning the
> same thing. But as I use the terms they're distinctly different... the
> "stain" being a fine (although grainy) tone over the paper, the
> "speckling" being larger, possibly irregular but usually shinier *specks*
> of color, more widely spaced, that is there can be perfectly white paper
> between them.
>
> I've only seen what I call speckling in cases of faulty size, although
> *staining* can be from many causes, such as dispersal agent or other in
> the paint itself, or paper that tends to stain... (as some will always if
> not sized, eg. one particular Arches which I'd have to look up to name).
>
> And frankly my experience of the experience is so different from what you
> describe, I really do hope that's the explanation.
>
> ....the chances of getting
> > speckling/staining on Rives is much greater than on Fabriano--maybe due to
> > the paper or the sizing. However, I got speckling on Fabriano when I sized
>
> The "Rives" here meaning Rives BFK, I assume, not one of the other Rives
> papers???
>
> Judy
Received on Sun Sep 4 16:08:48 2005