To expand on an my earllier posting. Another way, which also works, is to
make sure that the paper has a 1 % gelatine size which is then dried
quickly in a blast of air, and then well humidified . Coat the paper
quickly and dry again quickly so that the solution does not sink into the
paper. Them humidify the paper again before exposure. This method works
for the papers I prefer which are Fabriano Artistico and Saunders
Waterford.
Terry King