The "Desmetcolor Method".
This system devised by Noel Desmet of the Royal Belgian Film Archive has been used since the 1970's to try to restore some of the strong colours and dramatic effects of early tinted and toned prints. It is not intended to match the colours of a particular print but provide an extensive palette from which to choose colours in the same way that producers chose the effects they wanted originally. Many early coloured films were duplicated to make a normal black and white duplicate negative and notes kept of the original colour before the decaying nitrate print was destroyed. Desmet's method enables these colours to be put back as tints or tones or as a combination using the archive duplicate negatives as a starting point.
The colours do not match exactly the originals although if enough trial and error time is spent quite close matches are probably possible. The overall dramatic effect is probably very close to that of the original. A number of laboratories use this method. The final print is on a colour print film.
Working independently Dominic Case in Australia has used a similar system but making the monochrome duplicate negative on Eastman Colour Internegative. This method was published in the SMPTE journal in 1987. The choice of material was probably influenced by the idea that a masked negative material would make a more stable starting point than a black and white negative. Comparisons of the two methods suggest that the results are very similar but the use of a black and white negative material results in finer grain on the final print.
THE BOOKSHELF
THE DESMETCOLOR METHOD FOR RESTORING TINTED AND TONED FILMS / by Noel Desmet, Paul Read