Originally Posted by Jordan
Thanks for your comments, and thanks also to Gerald for the pH data.
OK, I mixed up some PC-Glycol this evening and ran a comparison test of it against a PC-TEA solution that I mixed some 2.5 years ago. For the PC-Glycol I used a 30% solution of sodium metaborate as the activator, and mixed the working 1:1:100. The PC-TEA was mixed 1:100. Both were developed for the same time and conditions. Development was rotary in tubes on motor base, i.e. with fairly fast rotation, ten minutes at 72º F.
The negatives are dry now and the PC-Glycol negative has slightly more contrast, which I think is consistent witht Gerald's data that indicated the metaborate would work at a higher pH than TEA.
Curves attached. BTW, the ES for this plot was set at 1.40 for a Pt./Pd. print, as you can see from the CI. For silver gelatin papers the ES would need to be much lower. Time permitting I will run families of curves for PC-TEA and PC-Glycol soon, which will of course provide much more meaningful data than just single curves.
BTW, the film used for this test was some of the JandC ASA 100 film from China. John sent me this film more than two years ago, and it has been stored at room temperature since then. And it still has a B+F of around 0.09, quite remarkable. And especially since it has excellent expansion potential, as you can see from the curves.
Last edited by sanking; 08-18-2006 at 01:08 PM. Click to view previous post history.