Re: Foxlee Gum Process

     Hi all,
     After I have waded thru 20 messages on Foxlee, I don't know who is
saying what so forgive me if I have it mixed up, but here is my guess:
     Foxlee was doing a variation of the Mariotype originally, that he says.
However, his was different in two ways: for one, he found there was no need
to keep bichromate in either the exposed first layer (which he developed
before pigmenting and thus most of the bichromate was washed out) or the
pigmented layer (he said keeping bichromate in either presented some
"uncertainty"). For two, he was able to use different colloids (gelatin and
gum, or starch and gum) in his two layers and get it to work. That is his
claim to "originality".
This is what I found so weird--that there would be hardening without
bichromate, as if what little bichromate left in the developed image could
possibly infer hardening powers on the pigment layer. Negative is used, btw,
not positive. There has to be hardening of some sort, or a one hour water
development, and the ability to use a brush, would certainly wash away an
unhardened gum or starch layer completely.
     BUT, with what Dave is saying, if I read it correctly, AND with the
fact that acids will insolubilize gum without exposure, I think what is
happening is that with pressure the layer of pigment is adhering to the
image gum left on the paper as per Dave's suggestion (glycerined pigment
adhering to the hardened gum layer where water does not soak in, but not
adhering to where the paper will swell with water, correct Dave?) but the
hardening that occurs to the layer is probably due to acid, not transferred
bichromate (which is why 36 hours was necessary; if it was developed right
away, the gum might swoosh off).
     To test this, I would suppose adding glacial acetic to gum for 36 hours
in a cup might be instructive.
     The fact that Foxlee and others practiced his process, as did Marion
practice his, means that something was going on, but that the "something"
they thought was going on, wasn't, is very likely.
     I'm really only interested in it because it seems like so much work
when they could be just doing a gum print the easy way. I think wanting
acclaim for new inventions was uppermost in their minds.
Chris
----- Original Message -----
From: "Katharine Thayer" <kthayer@pacifier.com>
To: <alt-photo-process-l@skyway.usask.ca>
Sent: Thursday, June 24, 2004 5:30 AM
Subject: Re: Foxlee Gum Process

> Chris,
> This is quite similar to Marion's 1873 (Phot News 17:242) observation.
> described by Galinsky in 1930 (Biochemical Journal 24: 1706-1715) that
> "if a dichromated gelatin film which had become insoluble by exposure to
> light under a negative were placed in contact with a similar but
> unexposed film and the two were squeezed together under pressure, the
> gelatin in contact with the exposed gelatin became insoluble after 8-10
> hours and a print of the image was obtained. It was concluded that once
> action was set up by light in a dichromated gelatin film, this could
> induce the same change in gelatin placed in contact with it, without
> exposure to light.... The present writer attempted to reproduce this
> change in the absence of any mechanical influence, and found that no
> such alteration occurred."
>
> She exposed dichromated gelatin until maximum insolubility had been
> produced, and then added a gelatin coating and left the whole in the
> dark for 24 hours, then for two weeks, and then four weeks, and found
> by analysis that there was no change in the added gelatin regardless of
> the length of time it stayed in contact with the exposed gelatin. She
> concluded that a more probable explanation for Marion's observation was
> that the squeezing caused the insoluble material to impregnate the
> soluble gelatin in contact with it, thus making it more difficult to
> dissolve, although there was no actual change in the added gelatin
> itself.
>
> Katharine
>
> Christina Z. Anderson wrote:
> >
> > This list has been so darn quiet this week I figured I might as well
post
> > another historical gum blurb!
> >
> > This is the oddest process, so just a point of interest that maybe
> > relates to nothing, or maybe something. It is the "indirect pigment
image".
> > Sized paper, gelatin.
> > paper sensitized with a 2.5% pot bi.
> > Paper exposed.
> > Paper developed so nothing remains except a faint positive.
> > Paper is dried, and can be pigmented right away as per below, or saved
for
> > weeks later.
> > To pigment: 5 parts 40% gum to 1 part glycerin to 2 parts acetic acid
to
> > 8-10 grains dry pigment.
> > Coat and dry the paper, leave under pressure for 30-36 hr, like under
books,
> > and then cold water develop, no exposure. It'll automatically develop in
an
> > hour.
> > Based on, get this, Foxlee's idea that the action of light set up in one
> > colloid is transferred to, and continued in, another which is not
exposed to
> > light at all. (mind you, no bichromate has been supposedly washed out
in
> > the water). Foxlee prefers to use starch as the sizing colloid, but
Griffin
> > prefers gelatin.
> > Advantages: no rush to develop. Pigmented coat not printed thru so it
> > doesn't need to be carefully applied. Hardening from bottom up, so it
is
> > more durable.
> > Weird
> > Chris
Received on Thu Jun 24 18:50:09 2004