Help about hdri and matte painting

[jagger]

Hi, I dont know how to do this, I would like to know how lighters do this in film (I mean in real film production).

The problem is: I have a matte painting of Mars, all in yellows/oranges. The backplate, which is a footage from a Red One camera is in clean blue sky, so the hdri is almost blue with big bright sun.

I want to use the recorded backplate changing the background of the image for my matte painting, the foreground will be color corrected to match then new background. Also I want to use the hdri to light a 3d asset and integrate it in the foreground, but as my new shot is all yellow/orange and my sky is blue the colors doesnt match. How is the pro way to do this?

Thanks!

[bepeg4d]

Hi jagger,
could you share some screenshots to better explain what you get and what you want to obtain?
ciao beppe

[jagger]

Hi, I cant upload images due to production privacy but I can show an example.

Hope this help to understand!

[ristoraven]

If it's clear blue sky, you should be able to key it out easily. Replace that with your matte painting, color correct the person accordingly.

Pro's do this against green screen..

[jagger]

The problem is not to key out the backgound, the problem is that the hdri is blue and the new scene is yellow, so when I light the 3d asset in the yellow scene with the hdri, the asset is blue

[calus]

The problem is not to key out the background, the problem is that the hdri is blue and the new scene is yellow, so when I light the 3d asset in the yellow scene with the hdri, the asset is blue

But what is your problem to make the HDRI yellow ?

If for some reason you can't apply to the HDRI the same color-correction you did for the backplate,
you can add in octane a "color correction texture" node between the "image Texture" Node and the "environment" node, then eyeball the "Hue correction" attribute to make the render of your 3D asset match with the backplate.

[jagger]

I know I can color correct the hdri, thats one way. But I would like to know how its done in film production

[ristoraven]

I wouldn't use blue HDRI for the asset if the final color would be yellow..

I would handle the red camera assets and the cgi assets on their own layers in After Effects and tweak them individually. Then, when they would be set close as possible to correct hue, I would add a bunch of tweaks to all of them on top to finalize the unified color tone..

[ristoraven]

I know I can color correct the hdri, thats one way. But I would like to know how its done in film production

They have ridiculous amounts of layers upon layers.

[jagger]

I MUST use the hdri to ligth the scene