Quote Originally Posted by gmikol View Post

--It's about 1/2 to 1 stop slower than the comparable dichromate-sensitized tissue, but with a much longer exposure scale (about log 3.0). This is 600-800 units on my NuArc. 800 units is about 20-25 minutes, which gets to be a little hot.

Geg
Typical exposure times for the UltraStable Color pigment films in a 26-1K plate burner ranged between 3 to 5 minutes. The need for a 25 minute (or more) exposure time baffles me. The Hardener No.3 absorption peak is 335nm and perhaps your light is emitting little energy of that nature. Alternately, the problem may be sensitizer (concentration, mixing technique or ?) related. Here's an example of how the sensitizer was incorporated into the UltraStable materials:

To make 250 ml of emulsion:

1. Add 1.5 g of Hardener #3 to 50 ml of water at 85F and QS to 60ml.

2. Slowly add sensitizer prep to 190 ml of a 13% pigmented gelatin prep at 105F.

Hope this helps..

Charles