Here is a 1982 Williams Time Fantasy playfield that we did several years ago.  This playfield started out to be your usual restoration with the average cracking in the original lacquer, ball marks and missing paint areas BUT it turned into a nightmare playfield restoration.  During the cleanup process we discovered that the original paint had adhesion issues with the wood surface.  The air blow gun was just blowing the paint right off the playfield.  Even after we removed the loose paint and base clear coated the playfield to lock in all the original artwork we discovered more loose paint.  Then the new damaged areas had to be repaired, feather sanded out and primed.  Then the playfield was base clear coated to lock everything in.  After all the adhesion issues were fixed then the restoration process started.  We almost gave up on this playfield.  We thought that the loose original artwork would never stop falling off.  It was actually base clear coated a few times before the repairs started.  No stickers, overlays or decals were used in this restoration.  Everything was either airbrushed or hand painted.    Over 50 hours of labor,  a lot of urethane clear coat (maybe a gallon of clear) was used and a ton of sand paper.  Not an easy restoration.