How do you invert a mask in Photoshop?

You can invert a mask in Photoshop to reverse its effect by using the Masks panel.

Here's how:

1. Open your image: Begin by opening the image you want to edit in Photoshop.
2. Select the Mask: In the Layers panel, make sure the layer with the mask you want to invert is selected.
3. Access the Masks panel: If the Masks panel isn't visible, go to Window > Masks to open it.
4. Invert the Mask: In the Masks panel, click on the three-dot icon located next to the mask you wish to invert. A menu will appear. Select "Invert Mask".

This will reverse the areas that are masked and unmasked, effectively inverting the mask's effect on your image. For example, if your mask was hiding the subject and showing the background, inverting it will hide the background and show the subject.