I think you should try a "futility" test. Process a small sample of your HPR paper without any salt or AgNO3. Give it a good long wash, and then examine it. I had an old batch of Revere Platinum ( from Magnani, not the current version of "Revere" ) where grey blotches appeared inside the paper after it had been wet ( with just water ) long enough. That is probably not the explanation in your case, but it is worth checking to avoid frustration of tying lots of "remedies" that cannot work....
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?