Hi Katherine,
I'll reply below with a "*" in front of my comments—sorry for the length of
this email (I had to coat it with KY jelly to get it to pass through my modem),
but I thought it important to include the discussion. I hope you get your
house cleaned tomorrow:
In a message dated 9/15/05 10:17:55 AM, kthayer@pacifier.com writes:
> Sorry, folks, this goes back to last Saturday but my task for today is
> cleaning house, which I'm avoiding by catching up on some of the mail I
> haven't read this week. A couple of further comments on a topic that's
> already played out:
>
> Ender100@aol.com wrote:
> >
> > Hi Katherine,
> >
> > I don't know if I would use the numbers as a test, since they are
> > pretty smallâ*”and on one side, the light is passing through the step
> > wedge and then through a layer of Pictorico, so there is more
> > spreading of the light and thus the white numbers are receiving some
> > exposure and it's not stain.
>
> This makes sense; I didn't realize that the step wedge was on top of the
> Pictorico.
>
> This is even exaggerated more because we
> > used tubes for exposure rather than a point source light It seemed to
> > me that when I compared the sharpness guide printed on gum vs on
> > Palladium, there is a difference with the gum capabilities (more "dot
> > gain" if you will) and this also shows with the step tablet printed in
> > both processesâ*”but that's nothing to say except an indication of
> > perhaps the limits of what gum can reproduce in terms of the ppi of
> > the file sent to the printer. But I wouldn't call one printing a good
> > test of this theory.
>
> 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 numbers—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. As I mentioned somewhere in my earlier post on these
pages, the fact that the 31 step is printed LAPPED over a clear strip of
Pictorico OHP film also exacerbates the spread of the light, resulting in blurring
the image and some density printed where it should be paper white.
>
>
> > There is a very slight amount of "stain" on the Glut hardened paper,
> > but it could also be fog.
>
> This is a very good point, which I didn't consider since I've never seen
> fog with gum. Certainly fog is a better explanation, and I retract
> completely my characterisation of it as "stain." I couldn't think what
> else to call something that appeared to cover the entire paper
> independent of the tonal areas, but certainly calling something
> removable "stain" makes no sense at all. I realized that after I sent
> it, but couldn't think what else to call it. 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 fog—I would suspect some low
level of exposure first prior to exposure. I don't think the dichromate gum
mixture would suffer from "chemical fog". I would not know what other issues
could cause it—chemicals in the paper—I could make all sorts of wild guesses
but that isn't helpful.
>
> We didn't test for that though. I also did
> > not use anything other than water development, so nothing was used
> > that might clear that area and give it the purer white of the edges or
> > backside of the paper.
>
> I think you may be confusing pigment stain and dichromate stain. There's
> no agent you can use to clear pigment stain. The clearing step clears
> dichromate stain only, and there's no evidence of dichromate stain on
> your samples. (BTW, To "clear" overall fog, you could flood the print
> with hot water or ammonia, as an alternative to brushing it off.)
>
> * No, no confusion there. I was referring to the ammonia-type trick and
> possibly other methods that might be used to clear pigment stain as opposed to
> a mechanical method such as brushing, hosing, or a slurry of cream of wheat.
>
> 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.
>
> The two samples though are clearly very
> > different and it wouldn't take me too long to pick between the two.
>
> Certainly, I'm not disputing that. Your observations are your
> observations, and as such are not debatable. The only thing I'm debating
> is the conclusion that's been drawn from the observed difference between
> the two samples. I can't explain the grittiness, or the fact that for
> you guys, the glyoxal doesn't prevent stain, because these are
> contradictory to my own experience. But I'm absolutely not arguing that
> you're not seeing what you're seeing. I'm only arguing that there is
> simply no logical basis for saying that the observed difference between
> the two samples on two very different papers is due to some inherent
> superiority of one hardener over the other, especially since
> contradictory observations exist elsewhere.
>
> * I wasn't making that conclusion. I pointed out that I would have to try
> the two papers and reverse the hardeners (next paragraph). In fact (and no
> offense to Don) I would want to do the size coating of both myself. It
> seemed, though, if I remember correctly, that Chris said that this result was
> consistent with her other experiences with the two hardeners.
>
> > However, to be fair, I would coat both papers with each gelatin and
> > hardner combination and test it that way.
>
> Of course, and this is what must be done before any statement can be
> made about the relative merits of the hardeners, even for this one
> comparison under this one set of conditions with these two papers. Then
> if one wanted to make a statement about the relative merits of the two
> hardeners in the world at large, many more variables must be controlled,
> beyond just the paper, and contrary observations must be incorporated
> and explained.
>
* I agree, a simple test with controlled variables and only changing one
variable—not even my undershorts.
> Katharine
>
>
>
>
> > Mark Nelson
> > Purchase the eBook & PDN System for Your Own Custom Digital Negative
> > Workflow @
> > Precision Digital Negatives
> > PDN's Own 31-Step Tablet Now Availableâ*”produced by Stouffer
> > Industries
> > Coming Soonâ*”Curve Calculator II will let you choose your toes!
> > www.MarkINelsonPhoto.com
> >
> > In a message dated 9/10/05 9:54:49 AM, kthayer@pacifier.com writes:
> >
> > Hi Mark,
> > Yes, I do see this, and I think it's a great idea; never
> > mind that I was
> > momentarily confused about how the 21-step prints in tone so
> > that you
> > can't see the numbers very well on the tonal steps. My
> > point, perhaps
> > not made clearly enough, was that on your print on
>
> > glutaraldehyde, the
> > white numbers don't print clear white but are occluded by
> > pigment in the
> > same way that the numbers on BFK are occluded by
> > pigment.  The idea
> > that on the one paper, the occlusion is a function of
> > exposure and on
> > the other, the pigment is a function of stain, simply
> > doesn't work for
> > me.
> >
> > I have never known gum to expose under the darkest areas of
> > a film step
> > wedge; for me there is pure white on the paper for those
> > areas. What's
> > being stated is that there is no area on any negative, even
> > the parts
> > that are meant to print pure white, that won't print with
> > some exposure,
> > in other words there's no way to get white other than to
> > brush off some
> > of the "exposure" later. To me it makes a whole lot more
> > sense to call
> > this stain, even if something about the size makes it easier
> > to remove
> > than stain on a different paper/size combination.
> > Katharine
>
>
>
>
Mark Nelson
Purchase the eBook & PDN System for Your Own Custom Digital Negative Workflow
@
Precision Digital Negatives
PDN's Own 31-Step Tablet Now Available—produced by Stouffer Industries
Coming Soon—Curve Calculator II will let you choose your toes!
www.MarkINelsonPhoto.com
Received on Thu Sep 15 17:23:16 2005
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