It is generally recommended when sensitising salted paper to do so with a 12% solution of Silver nitrate.
When performing the coating step, do Try to use the contents of the bottle labeled "Silver nitrate 12%" rather than the identical but unlabelled bottle that contains only distilled water.
Failing to follow this advice may result in rather low contrast prints ...
Not yet, but they run tests now at drinking water intake points to see what kind of medicines and drugs are used and thus found in our open waters ....