Quote Originally Posted by piu58 View Post
If you use print developer longer you'll get longer development times. This is not due to en exhaustion in a closer sense but of the increased concentration of bromide, which reduces development speed (but prevents the highlights form getting gray). To reduce this effect one could use print developer based on Phenidone. I don't know whether such a dev exist. Phenidone reacts lesser to bromide.
The thing with last night's prints, wasn't that they developed too slow, or even slower. The MGIV developed in normal time, the Foma developed too fast. I had expected little to no action, as the solution was mixed Saturday and used for 4 days, with yesterday being the 5th day. Of course, only printing a total of 20 5x7s shouldn't exhaust it too much, but the time in a half full bottle will cause oxidation and a loss of activity. The issue with the Foma, that I hadn't caught, was that they add developing agent to the paper. That's why the times were shorter. The Ilford, without the agents, developed normally.

I will try to use it again tomorrow, just to see if it's holding up. If it lasts a week, that should be good for me, as I can mix it up a day or more before printing.

I would still like to find out more about the use for highlight control, and any impact it might have on the rest of the process.

As for the phenidone tip, that's interesting to note, thanks, I'll check into it.