Most old photo papers used silver in their emulsions.As time passes this silver tends to migrate to the surface of the print creating tell-tale metallic patches.Light energy alone, usually from the sun, reacted with the light sensitive chemicals on the paper’s surface to produce an image.They only needed to be fixed to preserve the exposed image.The printing of the photographer’s or manufacturer’s name on the back of real photos was an expensive proposition.This practice was only cost effective on cards printed in large numbers; individuals and small photo studios could rarely afford to do so. While many amateur photographers numbered their cards this was most often done by larger studios.lthough real photo postcards were made in a variety of ways, they hold one identifiable feature in common.The tonalities of photos are completely continuous to the eye producing true greys, for they are created by the reaction of individual photosensitive molecules to light rather than the transfer of ink from a plate.
This gives these images a very matte look not normally associated with photography, and making some easy to confuse with collotypes.
Sometimes a photographer might expose a logo onto the image or hand stamp a name to the back of the card. Numbering was an essential way of keeping tract of large inventory.
The presence of a photographers name is not a definite indication of when a card was made or even who made it.
But even here the effect is more of a softening of detail than a observable texture.
Early real photo postcards are small by their very nature and since most were contact printed, not enlarged, there is no visible texture.
Many other brands of photo paper were also manufactured in Europe but rarely left the continent.