# Using layer masks

Layer masks are used to partially hide the contents of a layer. The hidden portions are still present in the image, but not visible; these portions are said to be masked.

## Tips for working with layer masks

- To add a mask to an existing layer, choose Layer > Add Layer Mask. If a selection exists while adding the mask, that portion of the layer will be made visible and the rest will be hidden.
- To choose a layer mask for painting and other operations, choose Mask in the channel selector. To return to the layer, choose RGB. For more information, see Working with channels.
- Painting on the layer mask reveals/hides portions of the layer; painting with white reveals, painting with black hides and painting with other shades of gray partially reveals.