"So maybe a chemist could look into this
test again and give some extra information if the ammonia will change the
o"
Surely as we are talking about tiny amounts of sulphuric acid, less than 0.1%,
in a tiny area for a very short time where the print has already spent a
relatively long time in a bath of 1 or 2 % HCl before washing, the effect of the
sulphuric acid, if any, in the peroxide is going to be de minimis. The lesson
here , in modern platinum practice, is never let HCl near your platinum prints.
A story to upset the conservation police. A rather ridiculous set of
circumstances once led me to pour concentrated sulphuric acid over a platinum
print. There is a small hole where the acid hit the paper but there was no
obvious effect on the platinum of the print. I use the print as a warning to
students to put acids in the right, ie poison, bottles and ensure that they are
clearly labelled.
Terry King