I don't have any experience with ethylene glycol but some of my experiments with ascorbic acid and phenidone in glycol suggest that if the mixing temperature is to high when you add the phenidone, say over about 250 degrees F, there is an increase in fog. I have not tested this enough to be absolutely sure that the premise is correct but adding the phenidone when the solution is at about 150 degrees F solved the fog problem for me.
Originally Posted by argentic
However, with the ascorbic acid + phenidone developers I have found it necessary to add a little restrainer to get fog levels down to what for me are acceptable levels. With Pat's PC-TEA formula, for example, using 9g of ascorbic acid and .25g of phenidione per 100ml of propylene glycol, I also add 0.2g of bromide. Using FP4+ as an example, the addition of bromide drops the B+f value from about 0.20 to around 0.10. This vaue is still higher than the B+f value of 0.06 that I get with ABC, PMK and Pyrocat-HD but it does not present any particular inconvenience in printing.
Last edited by sanking; 08-13-2004 at 12:37 PM. Click to view previous post history.