Hand colouring/ tinting/ staining

'Hand colouring' refers to any method of manually adding colour to a black and white photograph (either to heighten the realism of the photograph or for artistic purposes). 
Hand coloured photographs were most popular in the mid-to-late 19th century before the invention of colour photography. 
Hand colouring can be done to any type of black and white photograph on any type of paper (if a shiny type of paper is used - like light sensitive paper for example - the shiny side can be peeled away to allow the colours properly soak). Any other forms of colourant can be used such as stains and tints. Keep in mind that not a lot of colourant is needed so don't use it to excess.

* A hand coloured daguerrotype by J. Garnier, ca. 1850