U of S | Mailing List Archive | alt-photo-process-l | Re: haunted GUM (i surrender)

Re: haunted GUM (i surrender)

Yes! Now that Christine and Loris mentioned it, I remember once using paper that I had coated with gelatine but not hardened (it was paper originally meant for oilprint). I forgot that it was not hardened and made a gum on it. The result was more or less the same as Phritz gets. All black.
Some papers can be used without sizing at all, but it seems to me that coating with gelatine and 'not' hardening doesn't work.

Tom Sobota

On Fri, Oct 9, 2009 at 8:14 AM, Loris Medici <mail@loris.medici.name> wrote:
BTW, those exposure times are for the usual UVBL lightsource and can be too
much for sun exposures. For sun exposures start with 5 seconds and go up
from there - making enough test strips.

Brush well the sizing; you need it to fill the deep pores only, w/o
completely blocking the surface!

-----Original Message-----
From: Loris Medici [mailto:mail@loris.medici.name]
Sent: Friday, October 09, 2009 9:09 AM
To: 'alt-photo-process-l@usask.ca'
Subject: RE: haunted GUM (i surrender)

Phritz, are you sure your previous batch of paper had inteed hardened
sizing? Is it possible you've problems in hardening the sizing? Such as: not
waiting enough before starting to print or not enough - or too much??? -
hardener in the sizing? Hardener going bad - does chrome alum keep in
solution? (If you're using a stock solution that is...) Can't comment about
tonal inversion but now looking at them again your examples looks like
printing on paper with unhardened sizing. (Not everyone has problems with
this apparently but I remember clearly it gave severe staining to some of
our master printers...)

Try to size few sheets of paper with dichromated gelatin. Never tried that
before but I'd start with 3g jelatin + 3g dichromate into 100ml (add the
dichromate after melting gelatin), coat, dry the sizing with a fan and
expose w/o a negative for 15, 30, 45, 60, 90 and 120 seconds, wash, dry,
evaluate and use the exposure time which gives you enough hardening and no
or little dichromate stain... Maybe your chrome alum is the real problem not
anything else? (BTW, you can try clear gum+dichromate as a size too.)


-----Original Message-----
From: phritz phantom [mailto:phritz-phantom@web.de]
Sent: Friday, October 09, 2009 3:44 AM
To: alt-photo-process-l@usask.ca
Subject: Re: haunted GUM (i surrender)


i will now size some paper, which will take one or two days to harden. i
will then make some more tries with sized paper.
gum is the devil