RE: Gum over Cyanotypes
Don, > Contributors to earlier threads on the subject of neutralising the buffer have discussed various acid alternatives. Ryuji Suzuki has suggested it is better to use a chelating agent. It appears that any acid will attack paper fibres - here is an interesting explanation from a commercial site: http://www.conservationresources.com/Main/S%20CATALOG/Acid%20Deterioration.h tm > But to what degree and how will it affect 100% cotton fiber paper. The link you listed mentions alpha cellulose fiber. Isn't that different than 100% cotton rag? Anyway I don't plan on debating the issue about HCl vs other acidifiers, I'm merely describing my practice and I don't feel comfy using HCl. I do know of one palladium printer in Mexico that swore by using HCL on Serroco <sp?> paper for ph adjustment(which I believe is no longer made and was manufactured by the Crane paper company and was primarily sold through Bostick & Sullivan). As for using a chelating agent I've not read where anyone has tried this for alternative process printing, in particular with palladium printing. Acidification with oxalic acid is definitely not good for acidifying paper for cyanotype printing and I'm not suggesting that. Normally I think of chelating agents being used to absorb iron in bleach for color film and paper processing not as a pH adjuster. Why don't you try a chelating agent to acidify with and report back to us about how well it works with cyanotype and palladium printing? As far as I know Ryuji doesn't do either. > Do you print your cyanotypes over glutaraldehyde-hardened gelatine? Yes. > If so, I wonder whether the gelatine would act as a barrier (so with a bit of luck the cyanotypes would never know there is calcium carbonate lurking back there in the paper fibres). > Do you print the cyanotype layer over the gelatin size? If not try it and I think you will be surprised with the result. I do know others who do and it works pretty well for them with Fabriano Artistico. Don Bryant
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