One additional point: Durland shows plates 36630-35 for both L perf and Bull's Eye perf. 36636-41 were also used just for those two. 36642-47 were used for all 3 perfs and 36886 was paired up with 36637-41 to produce Bull's Eye and EE perfs. It appears that L perf and Bull's Eye were before EE perf. Were they released the same day, or did one precede the other? I don't know where to find that kind of info.
Lars
I have Scott Specialized for US and a Durland Plate number catalog, but neither provides EKUs for 1580, 1580B, or 1580c. The reason I am curious is that if 1580c (L perf 10.9) was issued BEFORE 1580 (Bull's Eye perf 11.2) and 1580B (EE perf 10.5 x 11.3), then the L perf should be the major and the other two would be minors according to Scott's apparent guidelines of major for perf difference of 0.5 or greater and minor for perf difference less than 0.5.
Actual issue date would be best, but EKUs would be interesting to know if issue dates are not available for each perf type. Does anyone know where that info might reside?
Lars
re: EKU for 1975 Christmas stamps US 1580, 1580B, 1580c
One additional point: Durland shows plates 36630-35 for both L perf and Bull's Eye perf. 36636-41 were also used just for those two. 36642-47 were used for all 3 perfs and 36886 was paired up with 36637-41 to produce Bull's Eye and EE perfs. It appears that L perf and Bull's Eye were before EE perf. Were they released the same day, or did one precede the other? I don't know where to find that kind of info.
Lars