Red to yellow..?

[Stig Olsen]

Desaturate the red first and use the color wheels instead of the hue vs hue. Also, learn some basic about how to make secondary colors with the curves. Horizontal manipulation on the blue curve in this case.
You can also use the channel mixer.

[Joseph Owens]

Had a very similar situation a few years ago for a “green” contest, but Honda supplied a RED Prius for the shoot. It took a couple of weeks of rotoscoping to change it to the legal Honda paint chip colour. Depending on the complexity of the shot… specular highlights, motion, dust, reflections, the tail-lights (which you might recall are also red) the color transform is neither simple nor straightforward to achieve at a cinematic quality level.

Down and dirty? You could try to qualify as much of the car as you can with a node tree (if required) that generates an alpha, then combine that with either a hue vs. hue curve, or an overall hue/phase shift on a parallel node. You may need to generate a travelling matte with a more sophisticated compositing application, because that is what you are doing. Its not, strictly speaking, exclusively a “grading” operation.

jPo

You mean “Old Ben”? Ben Kenobi?

[Knut Jansohn]

Hi,

You might count brown as a dark version of yellow 🙂
So what to do is: simply ad luminance!

Regards

Knut