I am trying to avoid the use of Formaldehyde and Glyoxal due to the obvious hazards. From my understanding the use of Alum, Chrome Alum and Arrowroot may not stand up to a lot of abuse??? Are there other formulas or procedures that are commonly used in painting that may be suitable? I've read the earlier posts on using canvas glue as well as fixer hardener, would there really be any archival issues with using the hardener that comes with fixers, would it be durable enough for many passes and abuse, how much water would I add, I use it with enlarged negs to one gallon of water.
Iíve used Gum Arabic and Potassium Dichromate to harden, it was mentioned in the book of alt processes and seems to work well, but I have difficulty getting the paper back to white. So far Iíve used it on Twin Rocker, BFK and have a few sheets of Arches Watercolor (300lb I think) which Iíll try today. Iíve shortened the exposures and have used a clearing bath. I'm up for any ideas, but in the end would break down and use formaldehyde if I can't discover any other options that suit my needs. I am able to get formaldehyde in a 3-4% solution which would be much less hazardous and if I did this how long could I plan to use the bath before it would need to be replaced??
At what strength would I mix Alum (not chrome) to give it a try as I have some on hand, or would this be a waste of time and paper? Iíve had some luck in the past with 1-2 layers un-sized and now I am making many more passes and see a definite need for sizing and hardening and would like to keep one more hazard out of my darkroom if I can.
Thank you all for the invaluable information I have found on this forum as well as others, I do recognize many names here.