1950s (?) Baseball RRPCs - Little Help!

[frankbmd]

It seems that the 50s date refers to color printing paper. Black and white dates to 1912 according to this clip

Although from its earliest years Kodak supplied materials used in the printing industry, the company first sold materials designed for the printing industry in 1912. That year, George Eastman acquired London-based Wratten and Wainwright, which made photo-materials for commercial printing.

In the decades that followed, the Kodak name became increasingly known in the printing industry. This success has been built by a number of industry milestones.

In 1929, the company introduced high-contrast KODALITH Materials, making it easier to prepare halftones for printing. Previously, printers used wet-collodian glass plates, which they had to coat themselves.
In the mid-1930's Kodak researchers designed and built the world's first electronic color separation scanner to prepare images for printing. The scanner was sold to a Time, Inc., subsidiary, and a version was ultimately used to produce the color sections of Time-Life magazines.
In the 1950's and 1960's, Kodak played a key role in the explosion of color in magazines and books. The company researched systems for high-quality color printing, and -- through numerous courses, conferences, and product introductions -- taught the industry how to do color separation, masking, and correction.