Re: Demachy and Maskell's postscript

Hmm. Idly re-reading the D&M postscript which is sitting here in front
of me, I see that they say that in their first attempts at this method,
the highlights dissolved away too quickly, but by adjusting the
proportions of materials they got better results. "A very little
patience and practice will teach each worker what is best for his own
requrements." Since I'm perfectly happy with my own methods, I guess I
don't have that much patience, but it's worth noting that mine are
apparently typical beginner's results for this method. But I agree that
it's not worth the bother of coating in two steps, even if I could
figure out how to make a print as good this way as the usual way.
kt

Katharine Thayer wrote:
>
> In spite of not having time, my curiosity got the better of me and I
> tried John's sizing method for this. I got mixed results; part of the
> problem was that the gelatin mix was heavier than I'm used to working
> with and I spread it too thick on one of the two papers I sized, and the
> prints I did on that paper didn't stick. But what's more interesting is
> that when the gum and pigment sloughed off of this paper, it revealed
> the image printed in dichromate in the paper below, which lends support
> to my speculation of the other day that what you're doing with this
> method is making a sizing image (photochemical reaction between the
> dichromate and the sizing) with a little hardened gum on top for color.
> I don't know what you would call this, but I wouldn't exactly call it a
> gum print. It's kind of like that "gold" jewelry that's made of some
> other kind of metal with a microscopic layer of gold on top, or like
> veneer over chipboard. Not to say that there's anything inferior,
> particularly, about a print made of gelatin with a little gum on top,
> only to say that it's not the same thing as a print made of gum
> throughout.
>
> I did get one very contrasty image that was interesting, though
> certainly not wonderful. In none of these attempts at replicating
> Demachy's method was I able to retain mid or highlight tones, although
> as I said the other day, I found that to be true also with the mixed
> emulsion containing potassium dichromate. And this was true even when I
> used increased exposures up to 5x the exposure that produces a good
> print with ammonium dichromate using this particular test negative. The
> potassium dichromate is just so much more contrasty than the saturated
> ammonium dichromate, I just don't see the point of it. But as I always
> say, each to his own.
>
> As before I found the separated emulsion no faster than the mixed
> emulsion. For whatever it's worth, the dichromate stain in these prints
> was yellower and the one image I retained was much more contrasty than
> the "Demachy prints" I made the other day on unsized paper or paper
> sized with a gelatin-gesso mixture or glyoxal-hardened gelatin.
> I've put two prints here for comparison:
>
> http://www.pacifier.com/~kthayer/html/Demachy.html
>
> Now today, I've really got to start thinking about doing my taxes.
>
> Katharine
>
> Katharine Thayer wrote:
> >
> > Grafist@aol.com wrote:
> > >
> > > In a message dated 11/04/05 21:13:21 GMT Daylight Time, kthayer@pacifier.com
> > > writes:
> > >
> > > > Grafist@aol.com wrote:
> > > >
> > > > > Katherine,
> > > > > Try sizing with a 10% gelatine + 5% corn starch mix and see what
> > > you
> > > > get!
> > > >
> > > > >
> > > > > In a message dated 11/04/05 18:11:47 GMT Daylight Time, kthayer@pacifier.
> > > > com
> > > > > writes:
> > > > >
> > > > > > John, I don't have time to do this, so I'll have to ask you to tell me
> > > > > > what you think I would get. Are you saying that you've done the
> > > Demachy
> > > > > > method using this kind of sizing and found that it worked the way
> > > > > > Demachy and Maskell describe?
> > > > > > Katharine
> > > > > ..........................
> > > > > Katherine,
> > > > > Yes! However, I too am very busy, at present, and do not
> > > have
> > > > > time to answer your question in any further depth. When you do get time
> > > > please
> > > > > do try it.
> > > >
> > > > 10% gelatin, 5% cornstarch, is there any hardener at all?
> > >
> > > ............................................
> > > Katherine, No hardener! Glad youre finding time.
> > > Bye bye.
> >
> > No, I'm not finding time, I'm just curious, sorry.
> >
> > It seems to me that what happens, at least in my own experiment with the
> > method, is that the dichromate reacts with either the internal or the
> > external size in the paper, maybe even more than with the gum that is
> > added on top. And this would be even much more true of an unhardened
> > surface size, I would think. So you get a dichromate-size image with a
> > little dichromate-gum-pigment on top to give it color, and all the gum
> > and pigment above it goes away.
> >
> > But at any rate I'm not terribly interested in following up with it,
> > because my only interest was to find out if there was some sort of
> > principle underlying it that could be used to explain something about
> > the dichromated colloid process in general, as my chemist friend was
> > assuming. Since it's clear that the effect is probably only specific to
> > a few paper-size combinations, it doesn't interest me at all, because
> > it's obvious that nothing about it is generally applicable.
> > Katharine
> >
> >
> >
> > At any rate,
Received on Thu Apr 14 19:09:59 2005