split tone look- how much to get in camera?

[sea_moth]

hey everyone!

I got into a discussion with a DIT about a low budget short I’m working on.

I’m working to create a very stylised split tone look. It’s a night interior, with neon/forest green coming from outside & warm light inside. I’m putting down some references:

My initial thought was to put an RGB light outside the window or a daylight lamp with gel.  My DIT friend suggested that an alternative would be to use just pure daylight from outside & create a LUT that offsets it to green & continue with that in the grade.

My gut is telling me to try to get as much of the colour as possible in camera (or at least a good way there) but is there a benefit in getting the green hue through post only? What are some of your tricks to approaching a split tone look? How far would you take the green/warm contrast in camera and how much would you leave to the grade?
What sort of adjustments would be in your LUT for this kind of split look?

thanks, hope everyone had a nice xmas! x

Topic

[Roger Deakins]

I have no idea why you would not want to create the look you are after in camera. I’m sure your DIT friend means well but you are creating the images not them. The image you post were no doubt shot to be the way they are.

 

[Stip]

Roger’s reply should seal the deal but I want to add that it will also most likely lead to issues in other colors. It would work well with a shot like the second reference picture. But once mixed lighting and skin tones ect come in, things will get messy. Power windows, parallel nodes ect will get thrown at it in timing in order to fix things.

You already have a clear idea of the colors, no need to work around it and end up with a fake feeling version of the references you posted.

[gabj3]

To define why it will cause you artefacts.

We spend much of our time keeping the green channel of any image acquisition as noise-free as possible. This is because, photopically, your human vision is most sensitive to the green part of the spectrum yada yada.

In all WB gains for the Alexa line cameras (and most), no gain is ever applied to the green channel.

To add green in post-production, you would have to gain the green channel, dependent on how much, this would introduce visible noise.

That being said, consider what you’re trying to achieve. Even with the ideology a camera is just data collection and a large part of authorship comes in display preparation and post production. You still need two different hues to make the selects easy.

To create a lighting effect in post is painful to make look realistic… when you can just light it.

Post is geat at de/emphasising or stylising an effect.

 

Infinityvision.tv

[dmullenasc]

If you have people in the frame, then it’s easiest to shift strong colors that are opposite of the faces, hence why blue screens and green screens are used for VFX. So if a background is pure blue, then it can easily be shifted to blue-green (cyan) or green without affecting foreground faces lit warm. Or if there is only blue in the frame and the faces are pure silhouette like in that frame from “Vertigo”.

BUT what about the blue light spilling onto the faces, perhaps in the shadow side, so the face has a mix of blue and warmth in that area?  Or any other area in the frame where the blue light is transitioning into the warm light, creating an in-between color?  Even in that scene from “Vertigo” there are other shots where the green light is mixing with warm interior lighting.

Now just shifting the blue channel towards green isn’t going to look as “clean” overall compared to if you had just lit with cyan light in the first place where the blending point of colors would come out naturally with that mix of green. And it gets harder as you go further from the original blue — you can get away with some minor shift to blue-green but turning blue to pure green is much trickier in those areas of mixed colored light. So in the long run, it’s better to just light it with the colors you want in the first place — why spend time in post trying to create that effect, with mixed results?

[Author]

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