Re: Gum over Cyanotypes
Yes, probably so... But that's impossible; for consistency I let the gum layer in peace for several minutes (7-8 mins. average), then dry it with a hairdryer until it doesn't shine like wet and it's dry to touch (not tacky anymore), then I humidify both front and back using a sonic humidifier (you should see me doing it; it's a ritual - totally consistent movements and timing, almost OC behavior - hehehe). Humidity is what I need in paper so that the gum exposures aren't too long. (+ I'm not sure, but, maybe dry gum layer is more contrasty too? - Don't want that!) If I can't affix the paper to a dimensionally stable support then I have to learn to expose the cyanotype layer when the paper is equally humid (= relaxed) as when printing gum - that seems to be the most feasible / doable procedure. Don't you think? Regards, Loris. 28 Nisan 2009, Salı, 7:31 pm tarihinde, davidhatton@totalise.co.uk yazmış: > > Hi Loris, > Maybe it's not only shrinkage but also MOVEMENT in the paper? I > suppose you should be drying the gum layer to the same degree as the > first cyano coat. > David > > On Apr 28 2009, Loris Medici wrote: > > 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, Salý, 11:17 am tarihinde, > davidhatton@totalise.co.uk yazmýþ: > > > > > > 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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