Color Space Transformation

[J. Bernard Vallon]

I'd really like to have a set of custom transformations (contrast, saturation, etc) in redcine that would mimic, not only film, but specific film stocks.

It strikes me, that there is an objective way to do this, and I dont know if its been done before. I take 2 test images, one with my RED and one with 35mm film (say, 5245) of some test patterns with lots of different swatches, and bring them both into the computer and view them on the same monitor, and match my RED to the film. Save the transformations and call it "5245". Theoretically, all I have to do is apply that transformation to red footage and i'd get a pretty good approximation on 5245, right? Bright, saturated blues, warm colors, mild contrast.

Do the same thing with some color reversal, some bleach bypass, etc. I could make a whole library.

The problems, I think, would lie in the film scan. Regardless, I think this would be a cool experiment. Plus, with nikons I could shoot with the same lenses, and remove THAT subjectivity.

Any thoughts?

[martinnoweck]

interesting thought ... but you really have to get high end scans, if you don't you can call your preset "5245 - bad scan" ... ;-)

[Graeme Nattress]

REDCINE is a raw conversion tool though. What you're talking about is a different kettle of fish.

Graeme

[Hrvoje Simic]

It looks like a job for Color.

[J. Bernard Vallon]

Of course I dont know which controls will be available on redcine, but it seems like it should work, as long as I can make the swatches to match.

I think I'll try it with a d2x and adobe camera raw. then ill see if i have any idea what im talking about.

[GlennChan]

A 3-D LUT should do what you're looking for. I'm not sure if there's anything convenient that you can download.

Though they won't be perfectly accurate (but then again, cameras aren't accurate anyways due to metamerism).

Film might have a lot more dynamic range/exposure latitude to begin with, which you can't match exactly.

2- S-shaped curves look close. You can have different shaped curves in each channel, that works slightly better.

[J. Bernard Vallon]

Metamerism (color), an exploration of the factors that can contribute to a color appearing different under differing circumstances

I love learning new stuff.

[GlennChan]

Really... because metamerism with film gets really complex (apparently; I don't really want to think about it myself). Each layer will block light from other layers... you can figure out the % of transmitted light by multiplying the transmission %ages of the layers before it. You have to do this calculation for each wavelength.

And then film has a s-shaped transfer curve... so I believe you have to factor that in.

And then some films have four color layers. So you have a lot of factors interacting with each other... more so than video cameras.