# Early Two Colour System



## Tim Tucker 2 (Mar 31, 2019)

I was reading up on Thomas Young and how after Newton he made the connection that the system of primary colours and how it worked was really describing the mechanics of the human eye and not the fundamental nature of light itself. When I came across a description of an early two colour system.

Basically it involved taking two B&W negs of the same scene through opposing colour filters. Then creating a positive from that neg and projecting it back through the same colour filter superimposing both on a screen. What I think they were experimenting with was just how little information the eye needs in order for you to create a full colour understanding.

So I decided to see if I could simulate it with digital and see what the results might have been.

I started with a suitable, but digitally processed image:






I then simulated a B&W positive shot through a filter that's slightly the orange side of yellow:





Then simulated how this would look if projected back through that filter, (its a solid colour overlay of H:52 S:76 B:96 set to *colour* blend mode):





I then did the same with a simulated filter that was just to the cyan side of blue:





And again simulated how this would look projected back through the filter (H:216 S:75 B:91):





Then simply overlaid the blue at 50% opacity on top of the yellow:





Though well short of a full gamut it's also quite impressive how colourful it looks considering how little actual colour information is contained.


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## zulu42 (Mar 31, 2019)

Wow, that's incredible! So interesting. Thank you.


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## zulu42 (Mar 31, 2019)

Have you tried a third filter?


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## terri (Mar 31, 2019)

Nice.   It came out looking great.   

One of the joys of B&W photography is the freedom the photographer has in the decision to add color, and how.   This 2-step process is similar to what takes place when toning silver gelatin prints - two tones, often starting with sepia or selenium, then a quick dip in blue.   Or copper and blue.   Etc.    

Lots of fun to be had playing with silver halides or, in your case, pixels.       Minimal color addition can lead to striking results.   

Nice job!


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## Derrel (Mar 31, 2019)

zulu42 said:


> Have you tried a third filter?



It's my understanding, that three B&W images, will give really good, rich color, and that the method was used, more or less, 100 years ago, for quite a few things... I recall seeing a diagram and some example photos in the old Time-Life series of books.


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## Tim Tucker 2 (Mar 31, 2019)

zulu42 said:


> Have you tried a third filter?



A three colour additive system based on a luminosity map is basically how your computer screen works, if you choose the right filters.


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## Ysarex (Mar 31, 2019)

The earliest color motion pictures were two color systems. They fitted the film cameras with a rotating filter synced to the frame rate -- half orange, half blue so that every other frame was either or filter color. Then they fitted the same rotating filter to the projector.



Derrel said:


> It's my understanding, that three B&W images, will give really good, rich color, and that the method was used, more or less, 100 years ago, for quite a few things... I recall seeing a diagram and some example photos in the old Time-Life series of books.



The Prokudin-Gorskii Photographic Record Recreated: The Empire That Was Russia | Exhibitions - Library of Congress

Joe


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