Mystery Card - 1928 Harrington's Smith

Ok, so maybe it's not such a mystery on WHAT the card is. The back of the card confirms that pretty well and SGC obviously found no difficulty in identifying the card either. But there is the question of HOW the card came to be this way. As you can see, we have a normal portrait of a ballplayer from the late 20s on an icecream card. Not such a big deal. The thing that makes this card special is that it's green. Harrington's, as are Tharps, Sweetman's and essentially anything with an ACC Designation of F-50 are ALWAYS found in black and white. Just like e107s, just like t209-2s, just like really any other black and white issue out there.

Full-sized scans can be seen by clicking on the thumbnail images above. As you can see, even the font on the back was done in green instead of the typical black color. Also, coincidentally enough, the Earl Smith card is one of the most difficult cards in any F-50 series.

If anyone out there has any information on this variation, I'd love to hear from you. I'm curious if there was a reason for this card turning out green or if it was simply a printing mistake. I'm also wondering if there are others out there like this. I've heard there might be one other Harrington's in green and even possibly a w502, the strip-card "w" version of the ice cream cards.

Thanks everyone!