Re: Archival washing at home
Thanks to Richard and John for the suggestions. Looks like I've got some shopping to do... Camden Hardy camden[at]hardyphotography[dot]net http://www.hardyphotography.net On 9/24/07 4:21 PM, "Richard Knoppow" <dickburk@ix.netcom.com> wrote: > > ----- Original Message ----- > From: "John E. Simmons" <productions@johnesimmons.com> > To: <alt-photo-process-l@usask.ca> > Sent: Monday, September 24, 2007 8:37 AM > Subject: Re: Archival washing at home > > >> I don't know for sure, and I don't really have a way to >> test. However, Ilford for their traditional materials, >> recommends multiple changes of water in a tray. It would >> seem that alt process would be the same - although perhaps >> a few more changes than for silver gelatin. The pump helps >> keep the prints separated, and in a large tray with several >> liters of water, it seems to wash just fine. A test with a >> hypo test kit shows no residual hypo - again with silver >> gelatin. >> j >> Camden Hardy wrote: >>> John, > > Ilford's recommendation is really to conserve water > although successive baths _with constant agitation_ may > result in better washing than in some running water washers. > For single prints a Kodak tray syphon works fine. The tray > should be larger than the print to allow circulation of the > water. Care must be used to prevent prints from clinging to > the bottom. > I am not at all sure if the process of washing for > alternative materials is the same as for silver-gelatin. For > conventional S-G coated on untreated paper (not RC) the > washing out is partially a diffusion process, mostly for the > emulsion, and partially frictional for hypo bound to the > paper fibers. It is the latter that results in the very long > wash times for "fiber" based paper. For silver-gelatin the > wash rate is also dependant on the pH of the emulsion > relative to its isoelectric point and the pH range over > which white alum hardener acts as a mordant. This may not > apply to the paper fibers. > It was discovered nearly fifty years ago that Sodium > Sulfite acts as an ion exchange medium for hypo. It is very > effective for gelatin emulsion but much less so for the hypo > stuck to the paper fibers. It _may_ be of use in alternative > printing process but I don't know what effect the sulfite > might have on some of them. Certainly it would not be > suitable for materials like Cyanotype which are bleached by > alkaline solutions. > > --- > Richard Knoppow > Los Angeles, CA, USA > dickburk@ix.netcom.com >
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