Electric Eye Presidential Issue (Prexies) FDC Dates

Also, the perforating machines were changed from being manufactured by Crown Cork and Seal for pre-electric eye rotary press stamps to being manufactured by Harris Seybold Potter for the electric eye rotary press stamps.

Here's mine. It has the markings down each side.

Beautiful Thomas Jefferson 3 Cent sheet - those will really beautiful engraved stamps back then.

Very nice stamp sheet. Is the plate number near the middle or on the corner of the sheet? The ones with the plate number near the middle are experimental electric eyes and for # 807 they are much rarer and worth much more. The markings on the left of the sheet makes me think that it might be the rarer plate block on the right. These experimental middle number plate blocks are collected in blocks of 10 for the best balance whereas the regular corner plate number blocks are collected in blocks of four. Sheets with the experimental plate blocks are much harder to find. Also, knowing the plate number helps to determine which it is.

I'll have to dig it back out and look at it to make sure that information is correct? I'll scan it if it does. I have a 2¢ partial sheet too and one has the plate number and one don't.

I think that the # 807 mint experimental electric eye plate number blocks of 10 with the number in the middle have a higher catalog value than the same # 806 ones.

Going through a box of covers today that I've had for a while and came across this one:

Here are some experimental electric-eye first day covers.