Colorist Tip #32 – Noisy Keys

Pulling a key in your secondaries? Be sure you watch the footage in motion and make sure the key isn’t too noisy. Few keys are perfect, but a noisy, noticeable key is unacceptable. If you can’t get a good key, try something else.

Keys are rarely perfect. There’s usually some bleed into something you didn’t want to key, and a few specks here and there that you did want but can’t seem to get. That okay in most instances, but sometime the key is just too noisy and you can see it jitter in the shot. I’ve seen it happen on DV footage, 5D footage, RED footage, even 4K 35mm DPX scans. No matter what your footage is or where it comes from, if you pull a key make sure you don’t only look at 1 frame. Watch the footage in motion, both the matte view and the actual correction in action. Ultimately, it’s about how it looks on the final shot, so if your correction is very subtle a semi-noisy key may be passable, but the matte view will give you a good idea if your key is going to be noticeably noisy in the final grade. And if you can’t seem to get a good key that isn’t noticeably noisy, scrap the key and try something else…

Bottom line, if you pull a key, watch it in action, not just 1 frame. Apple Color users, I’m looking at you. Since we can’t grade in real-time like Resolve, Lustre, Baselight, or any of the others can, we have a tendency to just grade off of a still frame then move on. While you shouldn’t do that regardless, if  you’re pulling a key, definitely don’t do that!

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