This section of the Panel is probably the second-most important section, after the Luminosity Selections section.

The “Modify” functions are designed to be used in conjunction with the Luminosity Selections section when the Preview switch has been turned to ON.

Let’s start by looking at them first.

Levels Button

When you have a selection preview active, press the Levels button to open a levels adjustment dialog box. Any changes you make to the levels adjustment will directly affect your selection preview. The main purpose of this is to adjust the contrast of the selection preview.

Preview with levels untouched
Preview with levels being adjusted for extra contrast

Adjustment Arrows

The 4 arrows next to the Levels button can be used to quickly adjust the selection preview in 4 ways:

  1. Darken Blacks
  2. Darken Greys
  3. Lighten Greys
  4. Lighten Whites

Pressing a combination of the Darken and Lighten buttons will have the effect of increasing contrast in your selection preview.

Invert Button

This button does what it says on the tin… It inverts the selection preview.

This is handy for a number of scenarios, but probably the most common is when you’ve spent time honing in on a specific tonal range only to realise it’s the opposite of what you wanted…

Selection that isolates the highlights and the shadows in one…
Inverted, this selection now isolates everything but the shadows and the highlights

Use Mask & Cancel Mask

Everything you do with the selection preview turned on is temporary. Think of it as a temporary workspace where you’re building your perfect selection before “bringing it in” to use on your main document.

When you’re happy with the selection you’ve created in Preview mode, simply press the Use Mask button to remove the preview and load the preview as an actual selection in your image.

You can then do any number of things with this selection, like apply it to the layer mask of a new adjustment layer, or brush through it into the layer mask of an existing layer.

Or, if for any reason you want to ditch the preview you’ve been working on, just press the Cancel Mask button and it will be like it never happened!

Build From Selection

This button will take any selection you have active at all, and load it into “preview mode” for you to view and modify, in exactly the same way as loading a luminosity selection in preview mode does.

This is useful when you have a selection that did not originate from a luminosity selection… For example if you load a selection using the “Select > Colour Range” tool in Photoshop to isolate the blues in an image, you can press the “Build From Selection” button to load that into the Preview Mode and then modify it using the “Modify” tools in this section of the panel. You could even add or subtract luminosity selections to or from it if you feel adventurous!

Load Mask As Selection

This button is really handy when you want to recycle a layer mask you already spent time creating and use that as the starting point for a new selection, or to use it again as-is.

To use it, click on the layer mask of a layer that already exists in your Photoshop document, then simply click the “Load Mask As Selection” button.

Then, if you want to preview and modify it further, click the “Build From Selection” button.

Show Layer / Show Mask

Use these buttons when you want to view the layer mask of an existing layer, toggling between the layer view and the mask view.

Simply highlight a layer in your layers panel, then click the Mask button to see it’s layer mask in the main window. Then click the Layer button to return to regular view.

Copy / Paste Mask

These buttons can be used to quickly copy a layer mask from one layer to another.

Take the following example:

To copy the layer mask from the Curves 2 adjustment, click once to highlight the layer in the Layers panel

Then click the “Copy” button in the Build & Modify Mask section of the Luminosity Masking Panel.

Then click once on the Levels 1 adjustment layer in the layers panel.

Finally, click the “Paste” button in the Build & Modify Mask section of the Luminosity Masking Panel.