Brightness Curve

[Marpel]

Couple questions:

1. If I click in the histogram to set a point, and I don't have the cursor exactly placed on the line, a point will be placed but the line will jump slightly. Without shift-clicking in the image, is there a way to place a point on the line with no line movement. I know the movement I reference is minimal, but the OCD in me screams every time I do this (should be a laughing face emoji here for this last sentence).

2. I am trying to better understand the Advanced Mode - What do the default settings represent? Are these just arbitrary settings that are recommended for most images? I ask this, because in the example given, the settings are markedly different from the defaults, especially in the Detail slider.

3. As changing the settings in Advanced Mode can cause quite subtle changes, is there a method, without completing the full operation, to visually observe the changes each setting will have. For some changes, to better see where those changes occur, I find I have to Composite the before/after with an Absolute Difference, then even use Levels and Colour to get maximum dynamic range, which seems a bit long-winded.

4. And last, is there a way to reset only the Advanced Mode settings, without resetting the curve itself?

Thanks,

Marv

[tomczak]

One pointer I know of is that if Details are set to zero, the preview image shows the BS-blurred (i.e. low pass) part of the image + the Brightness curve applied to it. You can then adjust Radius and Threshold to see what's getting blurred and subjected to the curve adjustments.

Forgot to add that Threshold=0 should be equivalent to the same but non-Advanced curve, regardless of Radius/Detail value.

[tomczak]

Another idea as to highlighting the changes is to use Compare after the Brightness Curve instead of Composite. I like the Moving Curtain or Blink, but there is also an Offset Difference with the Strength magnification slider. You still will have to go back and forth between the two transformations to see the difference as you make adjustments, but it's pretty easy to do that.

[jsachs]

1. The only other thing you can do is enlarge the transformation dialog box which will make the curve larger and give you more margin for error. Adding control points can also change the shape of the curve.

2. The settings for Radius and Threshold are the same as for Bilateral Sharpen. The Detail slider increases or decreases the amount of fine detail in the result image, somewhat like sharpening.

3. Compare is better than Composite for this.

4. I have added a new reset command to the settings menu for the next release.

[tomczak]

Curiosity again: is the 'Temporarily Reset Curve' button in Curve Control any different from Shift-clicking on the Mask button in the Amount slider?

[jsachs]

It depends on the transformation. The Amount slider turns everything on and off while the Curve button just sets the curve to a diagonal from the LL to UR corners.