What you want are the Kodak HT-2 (residual hypo - wash test) and ST-1 (residual silver - fix test) tests. These rely on matching a stain on the test area to an indicator strip, which is no longer made by Kodak. However, you can pick one up online; I think there's a pdf version on Ed Buffaloe's site,
www.unblinkingeye.com in the formulas section. You can mix both of these tests from scratch chemicals too if you have them on hand. Watch out for the shelf life.
For residual silver, you can also use selenium toner if you have it on hand. It is close to the ST-1 test in accuracy if not equal. Check out the details here:
http://www.apug.org/forums/forum37/82926-selenium-toner-fixer-test-2.html .
Here is the Kodak recommendation for using KRST as a residual silver test:
Kodak Rapid Selenium Toner 1+9 with water (
according to Tech Pub. J-1, 1973, p.41. Undiluted KRST may be better; see link above.)
1. Place a drop of the diluted solution on a squeegeed, white margin of a print or a clear part of film.
2. Wait two to three minutes; then wipe off the drop with a clean blotter or cloth. Any discoloration other than a slight cream tint indicates the presence of silver. Refix.
Here's the formula and instructions for the HT-2 test:
"Kodak® Hypo Test Solution HT-2
Distilled Water 750 ml
28% Acetic Acid 125 ml
Silver Nitrate, Crystals 7.5 g
Distilled Water to Make 1 l
(Store in a tightly sealed brown glass bottle away from strong light sources. This solution stains everything it touches, so don't splash it around.)
To use for paper, place one drop on the border of the print, let it stand for 2 minutes, then rinse with water. If the print is thoroughly washed the solution will produce only a very faint tea-colored stain, or possibly no stain at all. If it is inadequately washed, the solution will produce a rather dark tea-colored stain. To judge the stains accurately you should purchase a Kodak® Hypo Estimator, which costs about $3. (No longer available I believe, but downloadable as I mentioned above.)
To use for film, cut off a small piece of film and drop it into the test solution for 3 minutes. Properly washed films should show virtually no discoloration."
Note that these tests should be done after all processing, i.e. after final selenium toning and after wash-aid and a full wash.
I recommend that you do the following to test your workflow. At the end of your calculated capacity for your fixing bath (second fix if you use two-bath fixing), fix a full 8x10 sheet of paper using your used fixer. Cut this into quarters. Wash these as usual, pulling one 10-15 minutes before your usual wash time, one at your usual wash time and the other two in similar increments after your wash time (keep track of which is which). Test centers and corners of these for both residual hypo and silver.
If all is well, then your workflow is doing its job. Still, it's a good idea to find the limits of your workflow, so continue working with that same fixer for a while and repeat the test (knowing, of course, that you will likely have to refix the prints you make after reaching fixer capacity. After another 30-40% of the fixer capacity has been run through, repeat the test. If the print you pulled form the wash first last test was okay, then pull even earlier this time; the idea is to find a print that tests bad, so pull at 1/4, 1/2 and 3/4 wash time to ensure one will be underwashed. (If any of the prints you tested on the first batch failed the residual hypo test, then you will need to extend your wash time accordingly and test that instead.) The idea here is to find where your workflow fails and then build in a hefty safety margin of, say, 25%.
After you've established your fixer capacity (throughput) and optimal wash time, each with appropriate safety factors, then simply test the last print through fix and wash for each session (or run a test print as described above). This is what I do.
Hope this helps,
Doremus
