Re: Gum over Cyanotypes
Hi David, The 300gsm (140lb?) paper had stayed at least 45-50 minutes in room temp. water (HCl pre-soak to get rid of the CaCO3 buffer + 5 water bath rinses 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 humidity fluctuations / which have a very pronounced effect on cyanotype), maybe that's the problem... Regards, Loris. 28 Nisan 2009, Salı, 11:17 am tarihinde, davidhatton@totalise.co.uk yazmış: > > > 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 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...
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