nworth;

The Rhodium Chloride sharpens the toe of the paper.

Ian;

I'm aware of what you say and that is why I said that it is similar to both Azo and Lupex, as this formula is a workable hybrid of both and by either using sulfur sensitization and oxidized gelatin or adjusting addition times and temperatures, the 'correct' result will be gotten. So, based on the above formula, I have seen Azo type results from 4 distinct formulas. Three of them keep less well and are harder to control for speed and contrast than the one I have chosen.

I have seen comments about the Rhodium Chloride being added just before pptn starts and others that state it should be run in partway into the pptn. This is another difference that I find in various formulas.

This can be simplified considerably (as we did at Kodak). My own version is quick and simple.

Bill;

You may be right but everyone asks me about Azo type contact papers even though I can make many other types. And a lot of money is riding on M&Ps efforts.

PE