Now let’s edit the mask itself. To make this easier, we need to make the mask layer visible on its own temporarily.

Click on the Mask layer and then on the Show Mask Only button.

Masks are always shown in black and white — never any colors. White represents the areas that are transparent and black represents the opaque, masked areas.

Looking at our Mask layer and its gradient, can you see what we need to do in order to clear out the center of the scalloped frame? (Make sure the opacity part of the gradient is visible before you continue.)

Since the first two control points on the left are white, and they correspond with the inner structure on the Box Trap layer, they are the ones we need to edit.

• Drag the first two points downward, making them black, so that the mask looks like this:

• Click the Show Mask Only button again (so it is no longer down) and make sure that the bottom three layers are now visible.

You should see the rippling of the TIA layer, the white tendrils of the Wave Trap layer, the bluish-purple structure of the Box Trap layer, and the dots of the Gaussian Integer layer — masked to only appear outside of the scalloped edge.

What is missing, though, is the little white edging we created around the scalloped frame.

With all the layers still visible, click again on the Mask layer. There are still some control points on its gradient that are preventing us from seeing the white edging.

Locate the two white points indicated in the screenshot below:

• Click on the first (left) of these two points and delete it.
• Click on the second point and drag it downward (making it black) and to the right, just next to the white control point.

You should now see the white edging from the Box Trap layer along the scalloped frame.