PRODUCING A "SIMULATION" OF THE ORIGINAL.

The greatest problems arise if the purpose is to produce a restoration that attempts to retrieve the original visual appearance, as seen by the cinema audience when the film was first made.

To achieve this in a reliable and believable manner it is essential to identify the system.

Only by identifying the original dyes, filters or tones is any correct simulation ever possible.

It is an essential part of restoration that the final result will probably not have the same visual appearance as archive print material because the faded dyes will be corrected. It is therefore essential to know what these dyes are and to know what they were like when freshly formed. High saturations and sometimes garish colours existed, which will surprise many archivists. Two colours used extensively in two-colour films of the 1930's and 40's were Prussian blue [sometimes called Iron-tone Blue] and an orange-red made from a mordanted dye or from Uranium ferrocyanide. Today these dyes look dim by comparison with the same dyes freshly made, and to simulate the original appearance it is necessary to match to the original hues and saturations rather than the faded colours we see on old film today.

It is inevitable that the following methods are simply a list of techniques. The technician will need to select from them in order to attempt any particular restoration and make calculations based on the contrast rule, choose the most relevant contrast control technique, ensure the straight-line sections of characteristic curves are used, and generally adhere to all the rules of good duplication practice.