1959 Postage Due Series Different Colors

Scott's specialized show only one color carmine rose on this series, but there are actually 4 colors. Judge for yourself.

Are not some wet printed and others dry printed?

The 3 cent 34283 on the left was printed before plate 35283 was broken and retired. 34283/35283 were paired. The one the right was printed after plate number 35282 replaced 35283. There are examples like this in the 2,3,5,8,10,50,$1, and $5 with the 34283/35282 pairing. The 10 cent 37877 was printed later. The 7 cent 35306 is a dull gum. All dull gums have a different color than any of the shiny gums. The wet and dry printing were done in J79 - J86. This was not done in J88 - J104.

To me, the 3 cent block on the right appears toned, rather then a different shade.

I'm not sure it is toned - I think maybe it was printed from a poorly wiped plate.

Here are all the denominations I mentioned above when 34283/35282
where printed with the new color.

I tend to agree with eyeonwall. It would be interesting to see the three cent plate blocks on 1 scan side by side from the back.

The pinkish color (far right) only occurs on J97 on plate 37876 and 37877. You can see the color are different on all three plate blocks.

Here is the J91 - 3 cent from the back. The old color is the one with the darker gum.

Postagedueguy, I can discern at least two distinct colors from the scans. What you are describing as the "new" color, as I understand it, looks to be a duller color with a hint of brown. Either a different paper was used with this color ink, or the ink seems to leave a yellowish cast on the paper from wiping. Very interesting.

Do these inks respond differently to long or short wave uv light?

I haven't checked them under a uv light yet. Plate 35283 was first sent to press on 1974/07/10 and cancelled on 1978/03/30 after 251,889 impressions. Plate 35282 was first sent to press on 1977/09/10 and cancelled on 1987/11/12 after 112,444 impressions. I know the plate for 35283 was broken and retired. So it must have been broken before
1977/09/10. Then it was replaced by 35282. Plates 34283/35283 were paired when printed on the rotary press (800 stamps per rotation). After 35283 was retired 34283/35282 were
paired. This is when the color of the ink changed since all stamps printed from 35282 have the new color.