In the paper making process, the top side of a web of paper (or the side that has not contacted the papermaking machine’s forming wire) is known as the felt side. As water drains down through the wire mesh – small fibers known as fines, fillers and sizing are lost. This in turn makes the felt side contain more of the fines, fillers and sizing than the wire side. Paper grain is less pronounced on the felt side making it much less “wild”. The wire side is the strongest side because the felt side of the paper contains more fillers. Printing on the felt side of a paper – also causes more debris piling on the blanket (which in turn can cause hickeys).
Things you may want to consider:
– The felt side is often NOT the preferred side for printing because of all the loose fillers.
– Have a folded piece? Your paper is more likely to crack when folded with the felt side on the outside. (And also when folded against the grain)
Typical uses for felt side of the paper:
– Letterheads are printed *typically* felt side up
– Watermarking is viewed right side up from the felt side
– Envelopes are printed/converted felt side out