U of S | Mailing List Archive | alt-photo-process-l | Re: ferri sesquichlorati

Re: ferri sesquichlorati

On 22-okt-06, at 16:06, Halvor Bjørngård wrote:
BTW, Is there a maximum number of layers for gum, one book I have claim
twelve or so, but have seen other claims of 20 .. ?
Hi Halvor,

The maximum number of layers is related to the strenght of the (rigid) package of gumlayers and the constantly expanding and shrinking paper fibers between wet and dry. I think 20 layersare way too much and only possible on a rigid (non paper) surface or on a paper that is made rigid by fixing it on a rigid surface.

My still workable (= near maximum) number of layers is 6 or maybe 7, but I try to do with less.

I also am very much interested in the 'ferric' hardening of gum especially from a environmental viewpoint. I'll do some experimenting too!