In preparation for etching a container lid, I've done some
samples on sterling plate. Two of the three were successful.
However, the third, (which of course is the most interesting) has
come out rather grey. I used a 5 to 1 nitric bath, for a good
slow etch. The most exposed parts of the plate were in the bath
for an hour and a half, the least, half an hour. The "greying"
does disappear somewhat under fine emery; however so does the
crispness. For interest' sake, I tumbled it for half an hour
with steel shot and ammonia - nothing happened.
Hints, suggestions, avoidance tactics for the next test?