Much like many other additive processes, the Wolff-Heide system was based on three black and white color separations printed consecutively on one film strip and projected through a rotary filter attached to the projector. However, the biggest conceptional difference consisted in the fact that the negative contained not only chemicals to sensitize it, but also three types of colorants, alternatingly applied for every three consecutive frames, destined to filter the light in order to obtain the three color separations (instead of relying rotary filters or several objectives). This was intended to reduce the amount of light that was needed during shooting as well as to simplify the entire process. In order to apply the colorants to the relative frames on the film strip, a special machine was required.
Original Technical Papers and Primary Sources
Anonymous (1924): Una nuova pellicola per la Cinematografia in colori. In: La Cinematografia Italiana ed Estera, 18,24, Dec., pp. 10, 12. (in Italian) View Quote
DE 607 327; FR 609 398; FR 668 040; BE 331 866; CH 141 062; GB 246 154; GB 332 893; AU 52426; ES 965 65A1