Friese-Greene Natural Colour Process ?

[Steaphany]

Youtube saw that I was interested in videos on the Autochrome Process and recommended this:

Colour film of London in 1927

Watch the video and you'll quickly see that this is 1927 color cinematography, not still photography as with Autochrome !

Trying to research the details, all I could find was Claude Friese-Greene which simply referenced the Friese-Greene Natural Colour Process.

Does anyone know how this was done ?

[nrt]

I had always assumed that these types of colour film were 'hand tinted' - that is painted frame by frame... which is nearly right - they are actually made by exposing every other frame to a red filter, then the next alternate frame to a green filter and then hand colouring the appropriate frames... that wouldn't take long would it!

Some are shot at higher frame rates to stop the flicker that otherwise results.

[Steaphany]

The Red / Green process was developed by Claude Friese-Greene's father, William Friese-Greene and failed due to not being true color and an obvious flicker from the Red Green frame transitions.

Quoting Wikipedia:
Friese-Greene's later exploits were in the field of colour in motion pictures. Working in Brighton,
he experimented with a system known as Biocolour. This process produced the illusion of true colour
by exposing each alternate frame of ordinary black and white film stock through two different coloured
filters. Each alternate frame of the monochrome print was then stained red or green. Although the
projection of Biocolour prints did provide a tolerable illusion of true colour, it suffered from
noticeable flickering and red and green fringing when the subject was in rapid motion.

Seems color cinematographic technology was a big area of photographic research in the turn of the century, 19th to 20th, not the one which recently passed, as shown by all the color processes listed here:

List of color film systems

and a test feel of footage from 1902 survived which employed Lee-Turner Colour:

World's first colour moving pictures discovered