TONING IN COLOUR FILMS.

An important source of information on toning are the various manufacturer's manuals produced during the 1920's. However some of the much later publications, such as Cornwell-Clyne must be used with care, as much of this data uses the term "toning" but referring to genuine colour film not coloured monochrome print film. During the 1930's toning techniques became sophisticated and were used to tone one side of a double coated film one colour, and the other side, another. These were not coloured monochrome films of the type discussed in this chapter, but were two colour [and later three colour] film prints made from colour separation negatives. These are dealt with in the chapter on the restoration of colour film. The colours used for these had to approximate to the two-colour primaries of blue-green [Prussian blue was frequently used] and orange-red, or the three colour primaries of cyan, magenta and yellow. Mordant dye toning and colour development as well as wash-off imbibition toning techniques were all tried.