Rat Laboratory - View-Master Commercial Proof Reel - early 1950s - vintageRat Laboratory View Master Test Proof Commercial Reel 1950 vintage 3D images in full color Proof reel from late 1940s early 1950s, It is possible that this test proof reel never went into production. TEST PROOF REELS: Before a reel goes into production, a test reel is made to check for cropping, color, sharpness, etc. These reels are for internal use only or to get approval from the customer, and are not for re sale or publication. They may be of