From: Breukel, C (HKG) (cor@lumc.nl)
Date: 07/05/02-03:47:23 AM Z
First: for those who are interested, I have put up a scan (and you know
how scans are a meager representation of the original) of the gum over
kallitype test I made (deatils at the bottom of this mail). The
resulting print can definitely benefit from one or more Gum coats)
It's at: http://www.medfac.leidenuniv.nl/lgc/gok.html
Judy Seigel wrote:
>
> On Wed, 3 Jul 2002, Breukel, C (HKG) wrote:
>
> > I ofcourse did pre-shrunk (per PF instructions).., but I tested a
> > size/hardening in one step (solute gelatine 1.4%, than boil it with 1
> > gram Alum per 500 ml, cool down and brush it on the paper).
>
> Cor, I hesitate to even mention this because you are the lab king -- but
> you are BOILING gelatin? I was taught (& every source I've seen says
> that) boiling gelatin "breaks it down."
..yes that is true, but this boiling gelatine and than adding Alum
recipe I found both in John Barnier's and James his book, It's quite
easy if you only seize a few sheets, so I gave it a try, but I was
puzzled by this boiling gelatine as well..it sems to work ok though,
clearing of the Kallitype and gum gave no problems..
> > BTW2: it is probably worth noting that the dichromate in the gum mixture
> > did NOT bleach away the silver image of the Kallitype: Simple theory:
> > the silver image is more in the paper fibers, wheras the gum layer
> > stastays more "on top" of the paper fibers..
>
> The size went on over or under the kallitype?
..first pre-shrink, seize, kalli and than gum...
Best,
Cor
Details gum over Kalli:
The negative is a 4*5 inch MACO 820IR film (yes infrared film) processed
in PMK Pyro. Got some realy excessive stained highlights, not realy
uncommen with Infrared.
Printing it on silver gelatine, VC, asked for excessive burning of the
highlights (tree leaves) of 2 stops with a filter 1 over the base
exposure (2 1/2).
Pre-shrunk and foam-brush sized (1.4% gelatine/Alum harded) Fonteney
paper was used.
Initial print was a slightly under exposed Kallitype (as written up by
Peter Marshall, originally by Thompson, see B&S web site for protocoll).
Printing time was relative excessive: 20 min, wheras a non Pyro neg
would usually print in the 5-15 min range.
Gum print was aimed at "filling in" the higlights: mixture 0.5 ml gum,
0.02 gram (!, long live the micro balans) Burnt Sienna and 0,5 ml
PotDichromate.
(BTW I realy wonder how people can maintain registration: even after a
pre-shrink step, and using only 4*5 I could not obtain perfect
registration)
Printing time was again excessive (no surprise, taking the heavy stain
in account) : 40 minutes (in my setup a gum print usually prints in the
5-10 min range). Overnight soak to clear (probably shorter would also
work, this was just covenient)
The resulting print was actually quite pleasing: shadow/mid tone black
grey, high mid tone/highlights light yellow.
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