[Idea] Expose Adjustment Layers' Channels in Layer Properties

[Herbert123]

Adjustment layers such as the Curves and Levels allow us to choose the colour model to work in (RGB, HIS, HSV, etc), and it would be really useful if the Layer properties could expose these channels as well.

This would allow us to quickly check and assess the influence of singular channels and their individual effect on the main image. Currently it is only possible to completely turn off the adjustment layer.

For example, in the screenshot below I applied a HSV curve adjustment to the image. But it is not possible to control each HSV channel separately in the layer properties: the channels shown are RGB only. Which is ALSO useful!

I would like to request that the HSV channels are added in a second row below the RGB ones.
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hsv_channels.jpg

[shijan]

I asked for something similar some time ago. But my request was for "Disable" menu setting for Curves and Hue Editor adjustments, to turn on/off each channel curve independently without reseting it.

Screen Shot 2025-08-13 at 9.11.40 PM.jpg

[Herbert123]

Both options, in my opinion, would be very useful to have.

[Vivi_Ram]

+1 for both. I really like the idea of a turning it on and off rather than a complete reset. It is useful in many situations.

I had another idea, which may have been discussed here before: I wanted to be able to basically Ctrl + Z/ Cmd + Z and go back one step within the adjustment panels.

For instance, if I am making a curves adjustment, I'd love to be able to just go one step back and forward accurately. The same thing across adjustments. Right now, if I hit the reset icon, it goes back to the very beginning.

Thoughts?

[shijan]

I had another idea, which may have been discussed here before: I wanted to be able to basically Ctrl + Z/ Cmd + Z and go back one step within the adjustment panels.
Thoughts?

Seems useful. But Adjustment Panel "Undo" should be independent from global "Undo" and should not be visible in Global Undo History list. It will be too many "history garbage" if each movement of adjustment slider will be permanently visible in list.

[Vivi_Ram]

Yes, this need not be captured in the global undo history. I agree it will be too much.

[shijan]

It feels like a little bit problematic in some situations:
If use normal Adjustment window, other UI elements are not active and Undo/Redo hotkeys could be used for Adjustment only. No problem here.
If use Adjustment layer panel, then all UI is active and it is not easy to understand which Undo is currently active. Even if adjustment layer is selected it is not always desirable to use Adjustment Undo.

Solutions:
Adjustment Undo could be done as special independent icons in global toolbar with own independent hotkeys.
Or it could be done with icons in each adjustment layer toolbar. Not an easy task i guess, because UI for each adjustment layer should be changed.

Screen Shot 2025-10-23 at 7.35.27 PM.jpg

[Herbert123]

My experience tells me that I would love to have an adjustment undo.

But I would like to remind everyone that it is already possible to cancel an active operation, i.e.: while dragging a curve adjustment, with the right mouse button, and it will reset to the last setting.

However, this is buggy right now. Here is an example: I first dragged the curve upward to increase the gamma. Then I dragged the curve downward to darken the image, and while dragging, I clicked the right mouse button.

It will undo that last action, and the curve will reset to the last position, but as you can see the image is still dark.

So that means that the curve will indicate a move to increase the gamma, but the image remains in the state of having its gamma decreased...
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problem.jpg

[Vivi_Ram]

@Herbert123 - This is great. I didn't know about this possibility. And I can confirm the bug, too. It is not working.

However this is essentially a cancellation of a step, right? Not a real undo and redo?

Because I want to be able to compare steps while making adjustments. Right now, there's no way of doing this - to be fair, in any known apps. I simply have to reset and start over.

Maybe the solution is within the right mouse button! You hold down the left mouse button and click the right mouse button, it goes one step back - like it does now. Click again, it "re-does" the step. This avoids the conflict with global undo/redo shortcuts and avoids the need for extra buttons in the UI of the adjustments panel. It's an elegant solution, don't you reckon?

[shijan]

I was thinking a little bit more about Undo for Adjustments and here is some more possible problems:
How exactly should they record undo history when Curve points or sliders are moved by keyboard or by scroll wheel? Record each tiny movement?
Special undo for most adjustments that use simple sliders feels like useless at all. It only make sense for curves-based adjustments and maybe for Levels and Hue/Saturation.

[shijan]

Maybe add those options to Curves and Hue Editor as menu?

Screen Shot 2025-10-25 at 1.16.03 AM.jpg

[Herbert123]

I definitely wouldn't mind a simple undo and redo option. Adding these in the right-mouse click menu is fine with me, but I'd like those to be custom shortcut key compatible then.

@Vivi_Ram That sound like an interesting solution. The question would be: is it exposed enough, and it might not be sufficient to capture all usage cases. For example, I would prefer an option that allows me to undo and redo multiple steps in these adjustments.

The right-mouse button cancel option is very handy, though (once it functions properly).

In Blender right-mouse clicking any option, slider, input field, etc. opens a context menu that includes an option to reset to the default value (the backspace is the shortcut key). The difference is that Blender relies on the mouse being positioned in the GUI item for the backspace key to work.

[Herbert123]

Perhaps the mouse scrollwheel could be used to quickly undo and redo

[Vivi_Ram]

I was thinking a little bit more about Undo for Adjustments and here is some more possible problems:
How exactly should they record undo history when Curve points or sliders are moved by keyboard or by scroll wheel? Record each tiny movement?
Special undo for most adjustments that use simple sliders feels like useless at all. It only make sense for curves-based adjustments and maybe for Levels and Hue/Saturation.

I agree that we don't need this for ALL adjustments. It will be an overkill. We mainly need it for Curves. But Hue/Saturation Editor + Hue Editor would be great additions. Just three adjustments which require comparison. And I don't mind the context menu to add these as options. That's a simple place to put it.