Thanks Felice, that was roughly how I understood it to be done. It's funny how it goes into great detail in every area except how the computer program actually determines the colour. It suddenly gets rather vague at that point.I suspect it's either stupidly complex or a trade secret.But it's incredible how the colour information was sitting under peoples' noses all this time.I know they used this process on the first episode of FireBall XL5. Did they ever bother with the remainder of the series? If so, that would well be worth an order from Amazon.When they first started test-filming Stingray, they used 3 cameras; one with red film, another with green and the other with blue.That was one way of getting a technicolour image but it was too expensive to film all the takes. So they began to use, what to us is, an ordinary colour film television camera, which was brand new then.So, the fact that we can now go back and get info from the film negative that is invisible to the human eye and reconstruct so accurately what the colour really was ... it makes you feel a lot less cynical and jaded about the 'image reconstruction' and 'image enhancement' that you see on Star Trek and Bladerunner and the like.It's become a popular joke how, in CSI, they'll take a speed camera photograph of a vehicle and 'enhance' it discover the fingerprint of the last person to open the driver's door.I exaggerate the point to make the point but not by very much.
Dream big and bold and daring.