Sometimes the problem is even more simple. I remember when the factory at
Wells took the Bockingford line out for major maintenance the identical
parallel machine took over Bockingford production, that there were subtle
changes in the finish to the paper that meant a major change in approach to
gum printing; like changing to Fabriano 5. Bockingford production is now
back on the original machine.
Keep trying new papers to see if they work for you, so that when there is a
change, you do not have a nervous breakdown.
Terry King