Posted By:
HankronNow that I know someone has a microscope:
First, I must note that I haven't owned a single Play Ball from any year (unless you count a Dover reprint) for many years, so this discussion of 'rim' printing does not neccesarilly apply to Play Balls.
Under high magnification (100x power or so) the halftone dots on many early cards and related will have an apperance like below:

There will be a dark rim or edge around the dots and printed graphics, and the little isolated dots will that those little crosses in them. If you look in the image above (about 100x power magnification), it almost looks like someone took a dark marker and traced around all the borders of the ink pattern.
Further, the lettering and order designs away from the half-tone image, will also have a dark and noticeable rim around the ink.
This type of rim under high magnification is most noticeable when the printing surface is smooth or glossy. On the rough back of a card, or on newsprint, it may not be noticeable.
Vintage cards and related prints that have this type of 'rim' printing, including 1913 National Game, 1947 Bond Bread, Sporting Lifes and Sporting News, most (not all) premium prints issued by magazines and newspapers. Also (alluding to the previous question about the World Series program), most Pre-1950 magazines and programs.
The key to the presence of this rim under high magnification is that this type of printing has not been used for cards, magazines or such for many decades. So, while the presence of the rim does not prove in and of itself that a card was from 1912 or 1915, for example, the printing is consistant with the period and would not be used on a modern reprint or coutnerfeit.
So, if you're in an antique store with your microscope, and you see a 1920 magazine premium that tickles your fancy. Check it out under your microscope. If it has the dark rim around the ink under high magnification, and there are no other problems with the item, you can be assured that it's vintage.
Lastly, there were other forms of antique printing used on cards (which will be discussed at a later time), so the lack of the rim doesn't prove it's a fake (unless it's known, like in the above examples, that the original were made with this type of printing). For example 1950s Topps and Bowman cards were not made with this type of printing.
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