Working Beyond RGB:
A Report from the Field

Reto Kromer presenting

Photograph by Martin Weiss

Lecture delivered at the 4th International Conference Colour in Film, at the British Film Institute in London, United Kingdom, on 25–27 February 2019.


Our journey starts by recounting some of the experiences we obtained when restoring historic additive colour systems, such as Dufaycolor, by working in the Y′COCG colour space with an ad hoc video codec rather than in the RGB colour space.

The main part is devoted to multispectral scanning of moving images and a video codec to process the generated data. This allows us to work in a classic restoration suite, like Diamant, on the band level and even on the bit-plane level of each spectral band. Supervised, semi-supervised and unsupervised deep learning techniques open new horizons of film and video restoration.

The final part will be the possibility for an entirely new video codec, which enhances the two mentioned, virtually allowing us to work with any moving image data.


The presentation’s slides (PDF, 12.8 MB).


Having graduated in mathematics and computer science, Reto Kromer became involved in audio-visual conservation and restoration more than thirty years ago. He was head of preservation at the Cinémathèque suisse (the Swiss National Film Archive) and lecturer at the University of Lausanne.

He has been running his own preservation company, AV Preservation by, and lecturing at the Bern University of Applied Sciences, the Academy of Fine Arts Vienna and the Elías Querejeta Zine Eskola in Donostia (San Sebastián). His current research includes colour spaces, look-up tables and codec programming and emulation.

He served as a board member of the Association of Moving Image Archivists (AMIA) during two terms.