The fact that Gesso is visible on the reverse side is technically not a problem. It has to do with whether a fabric is tightly or loosely woven. In the latter case, it is more likely to occur. It is not so nice to see and can easily be remedied by first applying a layer of Amsterdam Acrylic Binder 005 before applying the Gesso. This seals the gaps in the canvas. Acrylic binder is completely transparent after drying.