[luciobar1980]

Ha! Very informative Steve, thanks! Yes, the one on the left is also has better registration which may have something to do with it.

Originally Posted by steve B

Differing colors are pretty common on Topps.
The card on the left seems to have a much more solid blue pass.

A few things may have helped cause it.

The exact ink colors were sometimes mixed by hand, the basic CMYK are manufactured, but with Topps printing some as solid colors instead of CMYK halftones they used semi transparent colors that could vary. For instance, a team with a green stripe would have blue and yellow overlaid, but the blue could be different is for instance a teal stripe was needed somewhere on the sheet.
And I've made that sound horribly complicated... It sort of is.

The other thing is that the inking levels are adjustable on the press. And they do have to be adjusted depending on temperature, humidity, etc. One day it may be better to run "lighter" which may or may not affect the shade, another day it may be better to run a heavier inking.

Also possible is a pass made after one made to adjust the color, where the offset blanket may have picked up two impressions of the color. They usually have slightly different registration, adding to the size of the halftone dots, and /or doubling the inking levels.
Alternately this can happen during registration adjustment, is the blanket doesn't transfer 100% of the image to the paper (Actually really common, just not usually severe enough to notice. )

Even a registration difference can cause a perceived difference in shade. Blue over yellow with exact placement looks green, If the blue isn't perfectly aligned, as it gets worse, the perceived color will be more blue.