greenscreen color correction question

[Brendan Coots]

This technique was used on Hellboy and other VFX-heavy films, so I know it’s reliable. That said, I typically only use it as a starting point and then color correct by eye from there, so there may be certain situations where it DOES fail and I just didn’t know it.

Are you changing the viewer to only show the red, blue or green channel when correcting with this technique? When you set the viewer to red, are you only correcting the red values? Can you provide a screenshot of the “blown out” stage, prior to correcting? It is important that you get it to blow out enough that it isn’t showing too much midtone range, but not so much that it is only showing extremes.

[Accountclosed]

Hi Brendan and thanks for replying.

Here are some uploaded files with blown out and the different color corrections. i uploaded the color corrections because i know i might not be doing something right there. anyways, thanks for responding and taking the time if you have a suggestion. Matt

blown out
https://matthewchung74.googlepages.com/blownout.jpg
red
https://matthewchung74.googlepages.com/redcorrected.jpg
blue
https://matthewchung74.googlepages.com/bluecorrected.jpg
green
https://matthewchung74.googlepages.com/greencorrected.jpg

[Brendan Coots]

It’s hard to tell without seeing the final result so I can see how the color correction is not working. From first glance, it looks fine.

I’m not assuming anything here, but is it possible we are talking about two different issues? This particular section of the tutorial is to get the basic tonal range and basic colors of the foreground plate to match your background. This does NOT mean it will instantly make your foreground actor look like it is properly situated into your scene.
For example, without seeing the greenscreen plate by itself, it looks as though your actor is fairly evenly and flatly lit, whereas outdoor sunny lighting is very direct (coming from the angle of the sun). Once you add the artificial highlights it will match better, but with this shot you will also likely need artificial shadowing on your actor. I guess what I’m getting at here is that maybe it isn’t the color correction that is throwing off your shot.

If possible, you could post a still of the final color correction, and a still of the raw greenscreen footage. This will help me troubleshoot with you.

[Accountclosed]

hey Brendon,

thanks again for taking the time. i realize that step was just for the color but something still seems off to me.

https://matthewchung74.googlepages.com/final.jpg

here’s the original greenscreen footage

https://matthewchung74.googlepages.com/greenscreen.jpg

i played with the exposure with a few different adjustment layers to account for the key and fill light and it looks better i think but still not quite …

https://matthewchung74.googlepages.com/playedwithfixingtheexposure.jpg

also i just realized you authored the article. thanks again for helping and writing the tutorial in the first place.

[Accountclosed]

hey Brendon,

thanks again for taking the time. i realize that step was just for the color but something still seems off to me.

https://matthewchung74.googlepages.com/final.jpg

here’s the original greenscreen footage

https://matthewchung74.googlepages.com/greenscreen.jpg

i played with the exposure with a few different adjustment layers to account for the key and fill light and it looks better i think but still not quite …

https://matthewchung74.googlepages.com/playedwithfixingtheexposure.jpg

also i just realized you authored the article. thanks again for helping and writing the tutorial in the first place.

[Brendan Coots]

The color actually looks pretty dead on, to my eye. The big problem keeping this shot from looking proper is twofold – the brightness and direction of the lighting on your actor, and the lack of a shadow on your actor similar to all of the other objects in your background shot.

The sun in the background shot appears to be coming from behind and left of the cameraman. In other words, it should almost be shining directly onto your actor from the camera position, just slightly from the left and high in the sky. The lighting on your actor, however is very flat aside from that bright patch on his pants that is coming from the wrong direction.

The best way to fix this would be to finish out the tutorial I wrote and add in some artificial highlights that appear to be coming from the camera’s direction, slightly high and left. Another thing giving the shot away is that everything in your background shot has pretty strong black shadows that are fairly long, given the position of the sun in the sky. Your actor, on the other hand, is kind of just floating with no shadow. Without this, your shot will never feel completely right.