U of S | Mailing List Archive | alt-photo-process-l | Re: Gum over Cyanotypes

Re: Gum over Cyanotypes

Depends on the paper. A paper that's internally sized with gelatin,
like Arches, does not respond well to a hot soak or a hot size; it
melts the internal size and moves it around. I've learned never to
use water or size hotter than 140 F on Arches paper. But my
understanding is that other papers, sized with non-gelatin material,
can tolerate it better.

On Apr 28, 2009, at 9:58 AM, Paul Viapiano wrote:

Does a long soak or hot soak like that destroy the internal sizing
in the paper?


----- Original Message -----
From: davidhatton@totalise.co.uk
To: alt-photo-process-l@usask.ca
Sent: Tuesday, April 28, 2009 9:33 AM
Subject: Re: Gum over Cyanotypes

Hi Loris,


The paper should be soaked in fairly hot paper to allow the fibres
to move one against the other and shrink fully. OR you could soak
in room temp water for 12 hours or so


On Apr 28 2009, Loris Medici wrote:

Hi David,

The 300gsm (140lb?) paper had stayed at least 45-50 minutes in room
water (HCl pre-soak to get rid of the CaCO3 buffer + 5 water bath
to get rid of remaining HCl and CaCl2) and dried before making the
cyanotype, doesn't that count for shrinkage? Does the water has to be
considerably warmer than room temp.?

Thinking again, my practice of cyanotype is to completely/
thoroughly force
dry the paper with a hair dryer before exposure (to be safe from
fluctuations / which have a very pronounced effect on cyanotype),
that's the problem...


28 Nisan 2009, Salı, 11:17 am tarihinde, davidhatton@totalise.co.uk
> Hi Loris,
> Give the paper a good long soak in warm water before you print
any layers
> at all. That's what I do and shrinkage is minimal on the print sizes
> I produce
> Regards
> David
> On Apr 28 2009, Loris Medici wrote:
> I did few gum over cyanotypes recently and I happen to like them
> See
> the most recent one below here: http://dwarfurl.com/008fa
> The print is on HCl acidified (2 minutes in 2.5%) Fabriano
Artistico EW.
> One -1/3 stop exposed cyanotype layer + 3 gum layers. (1. PR206
5% AD
> +1/3
> stop exposure, 2. PV19 Rose + PBk9 5% AD normal exposure, 3. PBk9
2% AD
> +1/3 stop exposure.)
> I print the Cyanotype on unsized paper, then size with 3%
gelatin. After
> sizing, the paper change dimensions and you can't register the
> negative
> perfectly on the first gum pass - 2mm larger in both horizontal and
> vertical orientations (print size 10x6.6"), the registration gets
> perfect
> only in the second or third gum pass. (See the resulting blur at the
> right
> edge in the middle.)
> My question is: How do you manage to get perfect registration for
> over
> layers?
> Any tips and tricks would be highly appreciated.
> Regards,
> Loris.
> P.S. I have read Lukas Werth's method somewhere else: Affix the
> on
> dimensionally stable support - such as an aluminum sheet - with
> print, varnish the print (acrylic binder + mineral spirit) to
> "protect"
> the gum layer and then put the print in warm water (this is where
> need
> "protection"!) to melt the gelatin and release the print from
> the support.
> I would like to hear about any suitable varnish that can be used
for this
> purpose too...