Those were search terms I used trying to find instructions to turn this:
Into this:
Now that it’s done, the procedure is more like: creating a mask (layer) using luminance, then invert mask data.
- Menu:
- Layers
- New Mask Layer
- From Image
- Dialog Box:
- Create mask from “source luminance”
- check “Invert mask data”
Mask is created in a group. Pair it up with a background layer.