Begin by cutting off a strip of the paper to be tested in very subdued safelight to total darkness. Since the paper I was testing was 16×20, I cut off a strip across the short side about two inches wide. I then cut the strip in half. This gave me two pieces of paper 2×8 inches. On the back of the paper I mark one with the letter ‘F’ and the other with the letter ‘D’ and place the latter into a light-tight box.
The strip marked ‘F’ is placed into a tray of fresh fixer and agitated for five minutes. Then it is placed in a tray of running water. Next the strip marked ‘D’ is placed into a tray of developer, agitated for two minutes. . . stop for thirty seconds. . . and fixed for five minutes. I use my standard print developing chemicals and the normal times. If you use different materials, use your normal times. Once both strips are in the wash tray, turn on the lights and wash for thirty minutes. Remove the test strips and dry as usual.
What has happened here is I have cleared the test strip marked with the ‘F’ which stands for fixed only and I have developed the strip marked ‘D’ for developer as usual. All that is needed now is to measure the reflected difference. I used an X-Rite 810 densitometer to measure the difference and found it to only be about 0.003, which is nothing to worry about. Keep in mind that all light sensitive materials, film or paper, will have some amount of base fog when developed.
Fortunately I was able to report to my friend that his paper was in excellent condition and he was happy to be able to sell it to another photographer. Hopefully this batch of paper will live on to produce some beautiful prints.