Frank,
I found this Peaches Graham scan in my collection and think it better illustrates the phenomenon that makes the Knight lettering look blue.
If you look at the green background above Peaches head you will see a patch of blue which is caused by a reflection off the baggie inside the BVG holder. These blue reflections can be seen throughout the front and back scans of the Graham and that is what you see on the lettering of the Knight card in question.
