1

I'm using SpeedGrade to do some coloring for my first time. It's coming along well but having a problem area in one part.

Here's the original:

Original Footage

Basic stuff I've done so far:

Color Balanced Footage

The issue is the "waves" on the home's roof becomes much worse after I balanced things a bit. Original closeup:

Original Closeup

After grading closeup:

Color Balanced Closeup

  1. Is there a term for this effect that I could edit into the Question title, and do a search for?
  2. Would the best way to fix it be using some sort of Mask with different color changes on the roof section, or is there some other method I should be looking at?
3

That's the moiré pattern, which is caused when the camera debayers an image with fine details: Wikipedia about the Bayer Filter (see the Artifacts section)

Many cameras have this problem, some more, some less. The best solution is to get to know the sensibility of your camera regarding moiré and - when you have objects like bricks, roofs, fine-detailed clothes - reframe your shot or zoom out.

In your case you had the moiré problem already in the source image, but amplified it with your color grading actions. The solution here is to have an additional node or effect before your general grading is done. This node/effect defines a mask with the roof and a subtle blur effect. Nobody will miss details in the roof, as long as the rest of the scene has detail.

(I'm talking about nodes, which is the way Resolve names them. SpeedGrade has some other terms that I don't know: Effects or Layers? But the concept is similar.)

1
  1. It's called moiré.
  2. The main enemy here is sharpness. Try to play with it... But now, when you know the term, I bet you will find solution shortly.

Good luck!

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