For the rotary presses used for Admiral stamps, hairlines on stamps occur from cracks on the printing plate due to stress from being bent. With regards to the only Canadian stamps that were printed from the U.S. Stickney press, they are as follows: Scott/Unitrade 162, 163, 163b, 164, 164ai, 165, 165a, 166, 166b, 167, 169, 178, 179, 180, 181, 182, 183, 191, 191a, 192, 195, 195d, 196, 196d, 197, 197c, 205, 206, 207. Thus, it may be possible that some of these stamps may also have gripper cracks on them. This may be something to look into. |