I have experienced two different kinds of "small black spots" (SBS) using
the Platine paper.
The first type are small specks which are already in
the paper when you receive it. If you look closely at the paper you may
begin to notice them. I never really noticed them until they showed up
in exactly the wrong place on a print. I've been told that this was more
of a problem with paper from early runs, and that paper made more
recently should be better.
The second type of SBS seems to be the result of using developer which
has a lot of sludge in it. It doesn't necessarily have to be "sludge",
it could just be "sediment" or whatever you want to call it. It just
metals which have washed off your previous prints during development.
HOWEVER, this alone does not seem to be responsible for the SBS. Itt
seems that in order to percipitate those SBS it is also necessary to have
some build up of unexposed sensitizer on your paper. In other words,
if you apply the sensitizer with a coating tube, it is quite easy to get
a heavier streak of sensitizer at the edges of the image area where you
finished your last pass with the coating tube and then just lifted it off
the paper. It is this heavy streak of sensitizer, which for me gets
masked off, which seems to percipitate the SBS. Therefore, I always take
a paer towel and wipe that straek down after I finish the coating. I
also rinse my coating rod after every two sheets of paper.
I hope some of this helps.
David