> > > Formaldehyde is a VERY effective hardener. It is used in >emulsion making and as a pre treatment for very alkaline >processes that soften emulsions. An example of an auxillary >hardener is: > >Kodak SH-1 Supplenentary Hardener >Water 500.0 ml >Formalin* 10.0 ml >Sodium Carbonate, dessicated 5.0 grams >Water to make 1.0 liter > >*Formalin is a 40% Formaldehyde solution >If monohydrated carbonate is used the amount is 5.9 grams. <stuff clipped> > > A more modern oganic hardener is Glutaraldehyde. This can >be added directly to developers. It is added, for instance, >to some of Grant Haist's monobath processes. > Note that Formaldehyde fumes are a powerful fogging agent, and Formalin shouldn't be stored or mixed anywhere near photosensitive materials. Apparently Glutaraldehyde is safer in this regard, though I don't have any first hand experience. Anchell and Troop give a formula for a Glutaraldehyde based hardener, as well as discussing adding it directly to developers. The downside of Glutaraldehyde is that it is harder to come by than Formalin, especially since Eastman went out of the organic solvents business. -- -tony San Leandro, CA http://www.shapesandshadows.com ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.