I won’t give a long description but I do like these “photographic” tiles. The process was developed by Mr. Carlidge during his long relationship with the Sherwin & Cotton company (1882-1911). From what I’ve read, the entirety of the process has been lost. We know, however, that he prepared a silver based gel that would be applied to a ceramic tile. The rough image appeared after exposure to a photo negative. From there certain light values were removed from the surface of the tile, leaving a thin relief. The translucent glazes, considered revolutionary at the time, furthered the effect. They are quite collectible now.
Helmar Sports Cards and Baseball History 