Before the advent of real colour photography, Quite a few 'Studios' would offer to produce colour images from their monochrome photographs.  In some cases this involved hand-colouring the monochrome prints with a brush and in a lot of cases the actual colours used were up to the photographer/artist.

Below are a couple that I found whilst rummaging around in an old Photo Album.

Over the years the colours in these photographs have faded quite a lot, but with a few tweaks in Photoshop some of the original image can be restored. Below is a simple but effective 'Auto-Level' adjustment.

This wasn't just limited to the early 1900's, as I remember seeing one that my father had done around 1950 or so.

1. WikiPedia page on Hand-Colouring
2. Colour Photography - The first hundred years 1840-1940
   Chapter 1 The search for colour
   Brian Coe - Curator of the Kodak Museum
   ISBN 0 904069 24 9