Apply gradient or mask to color wheels filter

Here is an easy way to apply color wheels to just an area of an image:

1) Make a duplicate of the image

2) Apply any masks you need to apply on the top layer, and apply the color wheels to it.

In Motion, you can turn just about anything into a mask. For example, you can draw a region with the bezier tool, and convert to a mask.

Here are two copies of Desmond, and I am drawing a Bezier line (coarsely, just for an example) around his head

:

When I close the Bezier curve it looks like this:

I add an Image Mask to the top Desmond, and choose this Bezier object as the source for the mask.

I temporarily disabled the bottom Desmond to make it clear that the mask is applied:

And now I added Color Wheels to the top Desmond, reenabled the bottom one and cranked up the saturation of his face. Compare with the hands, for example:

First the simple things: can you apply a color correction only to an area of an image? SURE, YES, OF COURSE.

You can add both Shape Masks and Color Masks to any correction. Furthermore, you can combine these masks in subtle ways, the masks can have feathering, and you can apply different corrections to Inside and Outside the mask.

Here is a silly example, using the silly character of Sir Desmond Glazebrook from Yes Minister:

Two shape masks in the general area of the face and hands:

and exaggerating saturation only in the masked area:

Yes, you can.

One way you can do it is to do a greyscale gradient and select the Luminance channel (instead of Alpha).

If the mask is static, it is probably best to create it in an image editor like Pixelmator or Pixelmator Pro.

Well, in Motion you have even more power and control, even if some things take a little more work to do!