Report from the Field #20
Restoring films as if they were videos
For example: Dufaycolor

When restoring old colour processes, like the additive ones used during the first half century of cinema, it is often more effective to handle independently the luma signal Y′ and the chroma components C₁ and C₂. Working with C_O and C_G is easier than working with the common C_B and C_R, because the de-correlation of the colour planes is better, and the transcoding from and to R′G′B′ is way faster, therefore one can check quicker the results on modern monitors.

Some good reasons to look at colours in film conservation and restoration from a wider point of view!

What and how

A short presentation by Reto Kromer, followed by an informal Q&A session and light refreshments. We will discuss the restoration of a film produced in Dufaycolor. The film has been digitally restored as if it was a video: the work on the black-and-white photochemical image (which matches the luma Y′) has been done separately from the work on the very tight colour pattern created by an etching process (the chroma components C_O and C_G). The MovIm video codec allows an efficient and transparent data handling of Dufaycolor in the Y′C_OC_G colour space.

Note that this will be a technical meeting, and the attendees should be familiar with high-school maths, including functions, linear transformations and elementary matrix operations.

When and where

On Friday the 6^th of March 2020, starting at 11 o’clock sharp, at AV Preservation by reto.ch in Écublens (a suburb of Lausanne, Switzerland).

As usual, the admission is free, but an inscription is required, as the places are limited to six at our small facility.

Notes

• As already done in February, we request the participants to wear the provided FFP3 masks and use our alcohol-based hand sanitiser.
• This was the last in-person presentation before a partial lockdown was ordered in Switzerland.
• We are very unhappy that our generosity is often betrayed, as many of our materials are distributed without naming their origin. Increasingly, others are even shamelessly claiming authorship of our work, which is just disgusting behaviour. And that’s the very reason why some resources are no longer freely available, but have been moved to password-protected parts of our website.

2023-02-17