What is this weird noise from hue vs lum curve?

So here's the image below, one is a widescreen full view, and the other below it is the zoom in one part of the screen to show you what I mean by the "noise".

Screenshot 2025-05-17 133820.jpg (311.82 KiB) Viewed 999 times

And here's the zoomed in part:

Screenshot 2025-05-17 133921.jpg (34.36 KiB) Viewed 821 times

Now, in the Hue vs Lum curve, there is a very slight lift in the red spectrum but what happens is when I bring it down, this "noise" goes away and it stays gone even if I lift it back up. What is this weird glitch? Here's how it cleans up in a split second the moment I touch that curve and then do whatever:

Screenshot 2025-05-17 V2.jpg (30.25 KiB) Viewed 999 times

I'd rather have it clean in the first place. I don't know why this is happening. It does seem like a weird glitch or bug given that this is non existent after the first curve move. It just vanishes no matter which direction I pull the curve to. Camera is BMPCC 4k, but I doubt that camera has anything at all to do with this. CSTs are being used too, one to take it from braw gen5 to DWG, and at the end, from DWG to rec709 gamma 2.4.

Running the latest Resolve V20 Studio update.

Hue vs. Lum adjustments can get you into noisy problems period, just from the nature of the control. My advice is to find another way to create the look you want. There are times when a key works better than a curve; there are times when Color Slice is better than a key; or cases where the Color Warper is better than Color Slice. All the controls have their limits -- the challenge is to figure out how far we can push the knobs before the image breaks.

There are also DCTLs that provide finer control (and more targeted results), and there's also ways of "ganging" 2 or more controls together to get what you want. A lot depends on time, budget, and creative intent.

Hue vs. Lum adjustments can get you into noisy problems period, just from the nature of the control. My advice is to find another way to create the look you want. There are times when a key works better than a curve; there are times when Color Slice is better than a key; or cases where the Color Warper is better than Color Slice. All the controls have their limits -- the challenge is to figure out how far we can push the knobs before the image breaks.

There are also DCTLs that provide finer control (and more targeted results), and there's also ways of "ganging" 2 or more controls together to get what you want. A lot depends on time, budget, and creative intent.

Thanks Marc. What DCTLs do you recommend? In that image, I need to reduce the overall saturation anyway and I tried that after posting here but even that HDR global sat reduction didn't do much. I just have to kill the hue vs lum.

Thanks Marc. What DCTLs do you recommend? In that image, I need to reduce the overall saturation anyway and I tried that after posting here but even that HDR global sat reduction didn't do much. I just have to kill the hue vs lum.

I'd have to see more of the problem to understand what you're trying to do. When I have problem areas within a frame, I usually try masking them off with a Power Window, then make the change inside the window. That way, I can constrain the effects of the sat change (or key or whatever) and stop any artifacts from happening.

There's a ton of DCTLs out there, and they're changing all the time:

Colorist Foundry Filmverse
https://coloristfoundry.com/store/\

Henry Bobeck
https://henrybobeck.com/dctl/UltimateSaturation

HotGlueBanjo
https://github.com/hotgluebanjo

Iridescent Color
https://iridescentcolor.com/shop/

Jed Smith
https://github.com/jedypod/

Kaur Hendrikson
https://store.kaurh.com/

Mononodes
https://mononodes.com/

Paul Dore 
https://github.com/baldavenger

PixelTools
https://pixeltoolspost.com/

Qazi's Toolkit
https://qazistoolkit.squarespace.com/

Ravi Shankar DCTLs
https://store.ravishankar.xyz/

Ravengrade
https://ravengrade.com/

Salamifish
https://salamifish.com/demos/

Sven Hegen
https://svenhegen.com/dctl-filmic-contrast/

Thatcher Freeman
https://github.com/thatcherfreeman/utility-dctls

Asim Siddiqui/XtremeStuff
https://github.com/xtremestuff/resolve-dctl

MonoNodes, PixelTools, and Thatcher Freeman's DCTLs are almost always terrific. Try a demo first and see if the DCTL will fit with your working style. Bear in mind that anything can break if you push it hard enough.

Thanks Marc. What DCTLs do you recommend? In that image, I need to reduce the overall saturation anyway and I tried that after posting here but even that HDR global sat reduction didn't do much. I just have to kill the hue vs lum.

I'd have to see more of the problem to understand what you're trying to do. When I have problem areas within a frame, I usually try masking them off with a Power Window, then make the change inside the window. That way, I can constrain the effects of the sat change (or key or whatever) and stop any artifacts from happening.

Oh wow, I only knew of two of these. SO MANY! Thank you Marc. I am gonna have to try some of these. What I am trying to do is not really hard (I hope so!). I just want to impart a creative contrast with some split-toning, colour density richness and finally restraining it all with maybe global hdr sat reduction (not sure but this one is the cleanest compared to HSV, maybe because it is colour-space aware? I don't know as much about this as you do). But these tools would certainly give me more options without tearing apart the image at least for what I am trying to do. I am not trying to do my own look dev or anything remotely close. I'd like to have something narrowed down for a tool for this sort of thing especially for my short film that I am crewing up for soon.

I went with Iridescent Color's tools. Filmic tone Curve, Density pro, will also get the Crosstalk one. I wanted to go with Pixeltools initially, but I am shocked at how inexpensive this one is for the absolutely high quality on offer here. I tested it on this braw image too and it never breaks the image. I tried his free tetra dctl and that one is sort of without guardrails so it does go deeper but introduces chroma chatter. I am actually never going to use the in-built "Contrast" control of Resolve now. I just prefer the saturation preserving contrast of this dctl and the options to adjust the black and white point with the toe and shoulder controls. Thank you again!