Technicolor 2 Strip & 3 Strip

Hi there.
photos by Luis Montemayor Flikr.

Download the script here> vfxtalk post
research>http://www.widescreenmuseum.com/oldcolor/technicolor2.htm

A few years ago when The aviator was launched, i made a research to obtain the same 2 strip and 3 strip color correction look inside the movie. After looking at the traditional chemical 2 strip and 3 strip Technicolor process i found that the magic behinds these look is derived from the restrictive nature of the filtering process in the lens of the Technicolor cameras.

These devices takes independent films strip for each channel component RGB using optical filtering. Then using prismatic reflections to integrate on one RGB beam, the full color image was reconstructed to the viewer.

For this reason to convert a full RGB image into the restricted pure channel RGB space nature of the Technicolors process depends on reproducing the optical filtering, creating control masks that represents the RGB values that are being mixed outside the Technicolor RGB space. I made up a shake script that recreate a pure color filtering lenses image using color reorder nodes that takes out the desired component. This way:

source

Cyan:

0GB

Magenta

R0B

Yellow

RB0

Then these images were weighted to each supplementary channel component (CMY) to represents in weighted mode how much of the complementary component was inside each channel. Finally these maps where multiplied and subtracted for each RGB component using the followinf formula

R=R-(MagentaMap*YellowMap)
G=G-(CyanMap*YellowMap)
B=B-(CyanMap*MagentaMap)

Finally the image was reconstructed reordering the channels. These technique generates a 3 Strip technicolor look, and for 2 strip i replaced the Green channel for the luma channel.



3Strip

2 strip

And this is a chart of the process.