Original Production Art Transparency used in proofing process. These are used for the production proofing process and is lifted off the orignal art. Usually one 1-2 of these are made per issue during the artwork stage. They often comes in two sizes. Small Size 8.5 x 11. Large Size 11″ X 17″. Many were thrown away. Digital printing made these obsolete, so you won’t find them outsidde of the 80s and 90s.