What kind of printing process would have been able to reproduce the smooth graduations in shade without halftone dots or the like? I just can't see how it could have been possible over eighty years ago. Here's another image contrasting the photo on the front of the card with the back: http://www.oli...

Hi all! I recently sold a signed card on ebay that belonged to my great grandparents. As far as I know it was genuine, but having received it the buyer has left this message: Hello! I recieved the card last Friday. I have been spending some time looking at it and it is obvious to me that the signatu...