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

Re: Gum over Cyanotypes

Thanks Jacek :)

You're right, if I size before cyanotype, probably the paper would change
dimensions much less (but then I will have problems with later / darker
gum layers, since with every gum layer paper shrinks more - due gum
shrinking in the darker=thicker parts... One way or another you hit that
wall!) therefore first gum layers will register better. That occured to me
too, but the problem is that I can't get a nice cyanotype on sized paper
(to gum requirements); bleeding is much more, tones are muddy (compared to
plain paper) and sharpness is less. To me, cyanotype has to be *in* the
paper, not on the surface...


28 Nisan 2009, Salı, 11:06 am tarihinde, Jacek Gonsalves yazmış:
> Stunning work as usual Loris! :)
> Question why do you size after cyanotype? Is it because the cyanotype
> bleeds after?
> Can you size, then cyanotype, then size again? or does this defeat the
> purpose, as it will shrink/warp the paper even more?
> cheers
> Jacek
> Quoting Loris Medici <mail@loris.medici.name>:
>> I did few gum over cyanotypes recently and I happen to like them much.
>> 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 gum
>> 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 paper on
>> dimensionally stable support - such as an aluminum sheet - with gelatin,
>> print, varnish the print (acrylic binder + mineral spirit) to "protect"
>> the gum layer and then put the print in warm water (this is where you
>> 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...