Charles M. Conlon, perhaps the most famous baseball photographer of the era, got his baseball photography start in 1904 while working for the New York Evening Telegram. He took photos that year at the Polo Grounds for the Spalding Guides. Conlon had long term relationships with the Spaulding Guides, the Reach Guides. Baseball Magazine and the The Sporting News.

Conlon is known for his 1909 iconic image of Ty Cobb sliding and the many intense close up portraits he took of many players from the 1910s onwards. Many of his original glass plate negatives still exist and were recently sold at auction.

Conlon did not stamp all of his photographs, although most had his handwriting on back. The most typical format is shown below where wrote the player’s first name out and then printed his last name is all capital letters.

It was also fairly typical of Conlon to scribble “Conlon Photo” on back and circle this annotation.

Conlon was unusual for baseball photographers of the era in that he used relatively few stamps for the decades that spanned his career. Dating is complicated by the fact he resided at his Alden address in Englewood, NJ for over forty years.

It is believed that his first stamp, which appears predominantly on his 1904-1909 photos is this one from his 111th Street address. Many copies of this stamp appear on his early photos in the Ernie Harwell Collection at the Detroit Public Library.

The following two stamps are his most common ones and commenced circa 1910 and were used for decades thereafter.

This stamp, which is rarely seen, was likely used in the mid to late 1910s.

The other stamp commonly seen is his Spalding/Baseball Magazine stamp. It is likely from the mid to late 1910s and onwards.

This Spalding stamp has been faked in recent years, but most fakes are in blue ink.