“Very Rare” Warner Bros. / Bob Clampett Prototype Animation Cel. Twetty Bird Prototype Cel. Warner Brothers/ Bob Clampett Productions Type. Pre-Production Black Line Prototype Cel. Studio black-line pre-production prototype cel. A Tweety Bird edition. This unique cel was used internally at the studio to guide color reference and character placement for the final limited-edition release. Prototype cels such as this were. Never made available to the public, and only a handful were produced for artist and studio use. Original Prototype Cel (Pre-Production). Warner Brothers/ Bob Clampett. 16.5″ x 13.5″ (unframed). Excellent overall; cel is clean and colors remain vibrant. Studio reference cel used for internal production guidance. We do not mark merchandise values below value or mark items as “gifts” – US and International government regulations prohibit such behavior. Feel free to ask questions…. Also check out our inventory as we will be adding some great, RARE pieces to the store!