Real Photo Postcards
Actual photographs had been mailed before, but real photo postcards exploded in popularity when the No. 3A Folding Pocket Kodak camera, which created postcard-sized negatives, came out in 1903. Real photo postcards are printed directly on photographic paper using photographic processes, not using a mechanical intermediary such as lithography, gravure, or halftones.
This 1913 real photo postcard depicts an intramural football team, the Krabs, at St. John's University. It is printed on Cyko paper.
This studio portrait of two boys holding up a northern pike they caught in Lake Sagatagan is a real photo postcard. It is from 1913, and printed on Cyko paper.
For information on finding the date of a real photo postcard by its stamp box, see:
Playle's Auctions, How to Identify and Date Real Photo Vintage Postcards.