Please Help To Identify Why They're A Big Color Difference Between These Two 1903 Franklin 1 Cent

One was blue green & the other one was dark green.

The bottom stamp is heavily toned, which could also affect the color?


Peter

Both were in 1907

Basically, it's partly because the millions that were printed of this workhorse stamp were not printed in one day using the same can of ink. Also, the top stamp has had ink more heavily applied, with a green cast added to the paper from the plate not being fully cleaned. The second stamp is indeed toned, adding a yellowish element to the perceived color.

It all adds up to a different color appearance. Do not apply what you see in very modern printing to printing of the past. There s even variation in modern printing colors as well.

Also, when comparing two stamps, they should be in the same scan to eliminate variability between separate scans.

OP, no offense, but just to make sure we're all using the same words, the first stamp has the slight discoloration at the tips of some of the perfs that is often called toning, and the second stamp is almost entirely toned.

There is also foxing, which is usually used for a discoloration that might look like toning but is actually a mold, which can spread. I'm always a little skeptical of which is which, so I segregate anything with the discolorations started on the perfs.