View Full Version : Advice on Hardener Sought

09-25-2011, 05:28 PM
Hi P.E. and All,
I now have a batch of Kuraray R1100 (silane functional PVA) based emulsion which already contains 2 dyes for green and red sensitization + S and Au for speed sensitization.
I now must decide, which if any, Hardener to use.
I have tested small portions of this emulsions with 3 different hardeners. Sensitivity to red light,as well as general slight fogging are both influenced by which hardener I used. For the test I coated each sample on white paper,,under IR light only, let dry, then exposed one portion to incandescent room light, them one portion to Red safelight only. Developed in D19.

No Hardener - mostly clean, with slight fog, weak red sensitivity.
Formalin- Very clean almost no fog week red sensitivity
Glyoxal-Cleanest. No fog. Weak red sensitivity. Short pot life.
Chrome alum- The most fog, but workable. Strongest red sensitivity.
The red sensitized portion (befor combining all 3 portions) was cyan in color as it should be. The combination of All 3 portions is bright levender in color.
PE- I recall one of your post, regarding one of your emulsions having combined Glyoxal with chrome alum. Now I am wondering what you gained by combining two hardeners.
I use D19 because it will show any tendency to fog befor any of the lower contrast workhorse developers.
Any comments / questions from anyone (even from Kirk) would be welcome.

09-26-2011, 03:11 PM
I can now add that:A) Chrome Alum is by far the toughest hardener as far as getting processed emulsion off of glass-using scalding hot water
B)Glyoxal is the only hardener that caused the emulsion to solidify in the pot. Both Formalin and Glyoxal emulsions are fully useable the next day.

09-26-2011, 03:13 PM
I made a mistake! I meant to write:"Both Formalin and Chrome Alum are fully usable the next day".