This collection you see below contains a number of very old ones, showing dogs from about 1900. All those postcards are in black and white. In the thirties it came into fashion to color these originally black and white postcards. In the fifties and sixties most postcards were still in black and white. From the seventies on most of the postcards where in color. It is remarkable how much variations editors did make with one and the same picture. You will find some good examples of this.