Hand tinted postcards began as a conventional black and white photograph and were painted by hand prior to production. In the early days the colouring took place in the photographers studio. As demand expanded factories were established employing large numbers of women to hand tint photographic images prior to postcard printing. The paints were oil based and transparent and their chemistry was such that many of the colourists were to suffer illness as a result of licking their brushes to form a point.
Our website contains a number of hand tinted postcards but none of Caspar until I found these two: