I got this card the other day, and, after taking a hard look at it, thought of this thread. Please take a look at each vertical border, at approximately halfway up/down the card. There are a couple of horizontal marks -- directly opposite from each other.
The right side is more visible -- a relatively bright blue horizontal mark. The left side is more subtle -- blue, but very light, almost transparent. It is hard to see in the scan, but it is very clear with a loupe. Below are scans of these marks.
The difference in these blues reminded me of post 131 in the following thread
http://www.net54baseball.com/showthr...+proof&page=14
So, what do you think? Are these some sort of printer's marks? Do they tell us something about the printing processes used?