Gradient Multi-point

[MikeG]

I've just realised that Multipoint/Fill/Blach and White, with 'match input image' checked, is a convenient way of producing a mask for the brightness curve in asituation where on wants to even up the brightness across the image - say the parts of a room distant from the light source. I don't like to think of the times before now that I could have made use of it!
However, that's by the way.
The real point of this post is to ask if anyone has found a use for mulit-point with color?

Mike.

[Charles2]

Can't speak to your Color question, but wanted to ask if you regard this technique as an equivalent:

A. Mask the dark areas
1. Use Brightness, stair step curve
a. create a new point on the axis near the left side
b. slide the point at the bottom left corner up to the top
this masks the dark areas
c. as needed, Undo and move the point you created to taste, selecting more- or less-dark areas
select more than you want, for the next step:
2. Blur the mask heavily, as much as 50; now you have the mask
B. Open Composite | Soft Light
1.Apply the mask to the Amount slider
2. Adjust amount of soft light to taste

The effect is to apply soft light to the shadow areas without brightening the rest of the image.

[den]

(1) I have used colored multi-point fill when creating a virtual textured background for an extracted main subject such as in a portrait... or perhaps a bird extracted from an 'as shot' background that contained too many distracting branches/leaves.

(2) My favored technique for ambient tone balancing or providing fill for an image is similar to Charles2.... using an 'active Mask image' which is a blurred 'negative' of the starting image's HSV-V channel as the Overlay image and the Input Mask image of the Composite transform in SoftLight mode:

Step1: click on the starting image; open the Mask Tool-Brightness Curve; 'lower left Apply - Add' the default diagonal curve; Invert; Blur with a medium to large radius; and leave the Mask Tool 'active' on the starting image.

Step2: click on the starting image; open the Composite - SoftLight transform; set the Overaly Image = 'active Mask image' and Overlay amount = 100 where the Input Image = the starting image and the Input Mask = the 'active Mask image'.

Step3: While monitoring an updating Preview, adjust to preferences the Composite tranform's Input Mask white/black sliders. Lowering mask white from 100 will decrease the lightening effect of the starting image's dark areas and raising mask black from 0 will decrease the darkening effect of the starting image's light areas. If the changes are not well blended or too soft, then click Mask Tool Undo and apply a different Blur: a larger blur radius will increase the blending and a smaller blur radius will increase of range of changes possible with the Input Mask black/white sliders.

[den]

Correction:

...from Step3... Lowering mask white from 100 will decrease the lightening effect of the starting image's dark areas and raising mask black from 0 will decrease the darkening effect of the starting image's light areas.

Should read:
Lowering mask white from 100 will decrease the lightening effect of the starting image's dark areas and raising mask black from 0 will increase the darkening effect of the starting image's light areas.

[Charles2]

Thanks, den! Use of the brightness curve in mask-making was a mystery, but your example illuminated the topic (excuse pun).

Other variants follow, such as: start with diagonal brightness curve, flip it by moving left point up and right point down, create intermediate points and stress the line into a reverse S-curve, apply, blur, apply, and save mask; then proceed with Composite soft light.

As a point of nomenclature, are these techniques close to what other programs call "fill light"?

[MikeG]

Whoops!
I jumped the gun big time with my initial post. Now that I've spent more time exploring multi point gradient it's clear to me that I just managed to fluke a multipoint gradient that suited the image I had loaded at the time. I did read the manual, but woefully mis-interpreted it.
How forbearing of you all not to point it out!

Thanks, Den, for another technique.

Mike.