Date unknown. As time went on and more countries allowed both address and message to appear together on the same side of the card, it led to some interesting instructions appearing. My next 'check' is the postmark. Because some countries still insisted on the back for the address alone, space continued to be left for a message alongside the picture. Also, the fine print on antique postcards is priceless - not only do you find manufacturers names, printing details and so forth, often there is a copyright date for the image on the front of the card!
I have quite a few postcards I am going to check them out for age.
My Save the Dates! I ordered Postcards in English AND Spanish! Tell me what you think!!
Married Life. Plain postcards began being issued by the Post Office. Allowed postcard sizes were specified: I love your collection. No other companies were permitted at this time to print postcards. I should make sure they're all dated.