Re: tonal inversion and pigment loads

Tom, Katharine et all,

I would say both your test and Katharine show some inversion, whatever you
did up to now, sizing, heavy sizing, half pigment load, extra long dev, etc.
Any of you have an example of a step tablet print that doesn't have this
inversion thing???

Thanks
Yves

----- Original Message -----
From: "Tom Sobota" <tsobota@teleline.es>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Sunday, January 29, 2006 10:54 AM
Subject: Re: tonal inversion and pigment loads

> Interesting. Your rightmost test strip is equivalent to the leftmost of
> mine, but the unexpected thing is that you got this
> result sizing more.
>
> My results are quite the opposite, which is not surprising given all the
> variables involved, many of them probably
> unaccounted for. As I commented in a previous post, I made a test on
> paper prepared for oil, very sized. A first coat
> of 7% gelatine hardened in formalin plus 2 additional coats of 3%
> gelatine. Normally you would let these two coats without
> hardening for oil, but since I wanted to test gum, I hardened them also.
> On this material I found only the slightest trace of stain
> as you can see here
> http://usuarios.arsystel.com/tksobota/SizingDifferences.jpg (the
> leftmost three strips, which are
> exposed 1min, 2 min and 3 min with the same mixture of Maimery Ivory
> Black as my previous tests. The paper used
> was Fabriano 5.
>
> The rightmost three strips show a very stained experiment, on Guarro
> Watercolor paper sized with two coats of acrylic
> gesso 10% in water. At other times I have used gesso sizing (without
> gelatine) without problems, even if I don't like it too much
> because it really intrudes on the texture of the paper. But this time,
> it stained horribly. Go figure. Perhaps it is the pigment
> with this particular gesso (Pebeo, made in China).
>
> My manifestations of terror of living near you were of course meant as a
> joke. I have also never killed anyone and my friends
> consider me a rather benign person. This is worrying, come to think of
> it ...
>
> Tom Sobota
> Madrid, Spain
>
> Katharine Thayer wrote:
> >
> > On Jan 28, 2006, at 9:24 AM, Tom Sobota wrote:
> >
> >> Sorry, Katharine, I have posted this image some weeks before with a
> >> clearer explanation of what it did mean. But taken out of
> >> context it is perhaps not very illustrative. Never mind, I'll try to
> >> organize this material better so it's easier to follow and understand.
> >
> > Well, I'm pretty sure I responded to this in context when you showed
> > it before, so maybe my response from then would be more illuminating
> > than my present puzzlement, who knows.
> >
> >
> >>
> >> Yes, living next door would be easier since surely we are looking at
> >> the same things and calling them different names. On the other
> >> hand, since you seem to be a woman of strong convictions, perhaps
> >> living in Madrid is safer for me :-)
> >
> > Gosh. I say what I think, but I've never yet killed anyone, or even
> > hurt anyone; I'm not considered particularly dangerous by those who
> > know me, and my next door neighbors aren't afraid of me, in fact they
> > like me. So you really needn't fear for your safety living next door
> > to me.
> >
> >>
> >> You know, I have been thinking about the fact that you have seldom
> >> found inversion in your previous work. Even these days
> >> in your tests, as far as I see, you seem to get easily pigment stain
> >> but not inversion.
> >>
> >> In my case it is very different. I get inversion when I want it, with
> >> different papers and pigments. With normal negatives and
> >> subexposition, or with Stouffer tablets, as you have seen.
> >>
> >> In a nutshell, I wonder if the very different conditions of relative
> >> humidity and temperature could make a difference. I gather that
> >> you live somewhere on the West Coast up north, not sure if in the
> >> U.S. or Canada, but certainly very humid. I live in a very
> >> dry country. Gum is sensible to humidity, as Kosar dixit. It is a
> >> wild guess, but I wonder ...
> >>
> >
> > Yes, I too have been thinking about how complex this is, and you could
> > be entirely right about the humidiity and everything. But just to
> > introduce more complexity into the mix, here's another wrinkle:
> >
> > Since the thing I was planning to do today was canceled because of the
> > weather, I thought well, what better way to spend the day then to
> > make a grid of test strips, varying exposure, pigment load, sizing,
> > see if I can discover the point at which I can reliably make an
> > inversion happen. So from the test strip I showed last night, I
> > decided to go both ways, less pigmented and then more pigmented. First
> > I cut the pigment in half and got a fairly good tonal scale, with
> > almost no stain, but a very light stain. So then I thought well, this
> > isn't a very heavy pigment load so maybe this stain really is
> > paper/sizing related, rather than pigment-related. So I printed the
> > same mix on a piece of the same paper I had that was sized with more
> > than the amount of gelatin I usually use. It turned out this size was
> > too heavy, and the emulsion flaked off right away. BUT, under the
> > flaked-off emulsion was a significant stain, more stain than on the
> > less-sized paper. I always seem to want to try to save an image that's
> > disappearing, so I grabbed it and dried it fast before the last two
> > steps flaked off, but afterward I thought that if I had left it alone,
> > all the gum emulsion would have left and there would would be just
> > stain and gum resist where the gum flaked off. I've tried the same
> > mix on the same paper several more times, at longer and longer
> > exposures, with varying (but not predictable) results, but always the
> > stain and partial inversions where the numbers came off, and most
> > crucially, always the flaking off of much of the gum emulsion due to
> > the too-heavy size, which would be the ruination of this combination
> > anyway, so there's not much point in pursuing this particular line of
> > inquiry further.
> >
> > This doesn't change my current feeling that inversion is a special
> > case of stain, and that stain is related to either paper/sizing or to
> > pigment, but I wouldn't have thought that a sizing problem would go
> > in this particular direction: more sizing equals more stain. I do know
> > from experience that more sizing causes flaking, but I've never seen
> > it cause stain at the same time. I've posted the results from this
> > mix on normally-sized paper and the first one I did with the same mix
> > on on the more heavily sized paper (the others are still drying) along
> > with the more pigmented mix from last night.
> >
> > http://www.pacifier.com/~kthayer/html/missingnumbers.html
> >
> > Carry on,
> > Katharine
> >
> >
> >
>
Received on Sun Jan 29 17:13:12 2006