Tinting by application of varnish
Very little information is available on this very rare process. Instead of immersion into a dye-bath the positive print was coated uniformly with a varnish. This technique can be identified by the lack on dyes in the perforation area and by the inhomogeneous application of the dye.
Original Technical Papers and Primary Sources
(1925*): Agfa Kine-Handbuch. Berlin: Actien-Gesellschaft für Anilin-Fabrikation. [* year estimated]
Cherchi Usai, Paolo (2000): Silent Cinema. London: BFI.
Read, Paul (1998): Tinting and Toning Techniques and their Adaption for the Restoration of Archive Film. In: Luciano Berriatúa et al. (eds.): Tutti i colori del mondo. Il colore nei mass media tra 1900 e 1930. = All the colours of the world. Reggio Emilia: Diabasis, pp. 157–167, on p. 157.
Read, Paul (2009): ‘Unnatural Colours’. An Introduction to Colouring Techniques in Silent Era Movies. In: Film History, 21.1, pp. 9-46, on p. 14.
Read, Paul; Meyer, Mark-Paul (2000): Colouring the Base (or the Emulsion Side) by Applying a Coloured Varnish. In: Paul Read and Mark-Paul Meyer: Restoration of Motion Picture Film, Oxford: Butterworth-Heinemann, p. 183.