[1966CUDA]

* sorry, this thread was originally posted in the 1950's buy/sell forum...now posting in correct area*

Just picked up these two Robinsons today at a collectibles show. Just wondering how the one is so dark. There was a box full of these 1947-66 Exhibits and several had varying degrees of the darkness. If you look you can even see the slightest hint of darkness on the lower right corner of the brighter one. Is this a production issue with the development of the photo image? The card is in great shape other than being dark with no creases. Backs of both are the correct tan color. Thanks for any insight.
-Claude