Re: Gum over Cyanotypes
Maybe heavier paper will do but the print is pretty small 10x6.6" to consider thick/heavy paper and those are very expensive to me (= special order, they don't stock HP 600gsm - only CP 600gsm, and I don't like CP texture). The paper is Fabriano Artistico EW HP 300gsm... This paper is a highly alkaline buffered paper, w/o acid pre-treatment you can't make it work "satisfactorily" for cyanotypes (or any other iron process). So I put it in very dilute hydrochloric acid (HCl) to completely dissolve the calcium carbonate (CaCO3) buffer before making the cyanotype. Regards, Loris. 28 Nisan 2009, Salı, 11:41 am tarihinde, Jacek Gonsalves yazmış: > Hi Loris, > > Thanks for the reply. > > Another option is to try a higher gsm paper? > > What paper are you using and what do u mean by "(HCl pre-soak to get > rid of the CaCO3 buffer + 5 water bath rinses to get rid of remaining > HCl and CaCl2)" > What is HCl and the rest mean? > > Cheers, > Jacek > > > > Quoting Loris Medici <mail@loris.medici.name>: > >> 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 >> yazmıÅ�: >>> >>> >>> 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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