This is a tutorial on how to add a layer mask in Adobe Photoshop.
A layer mask is a reversible way to hide part of a layer. This permits us to have more options when editing than permanently erasing or deleting a part of a layer. Layer masks are useful when making image composites, cutting out objets for use in other documents. Black white or gray are the colors that we can add to a layer mask. A way to do this is by painting the layer mask. If you paint it black it will conceal and if you paint it white it will reveal. And gray partially hides the layer that contains the mask.
Creating Layer Masks
Step 1: We select a layer in the layers panel.
Step 2: Then we add a layer mask by clicking the add layer mask button at the bottom of the layers panel. Then in the selected layer, a white layer mask thumbnail appears on the selected layer, and this shows all that is in the selected layer.
Black to conceal
We can hide the layer that has the mask in it by adding black to the layer mask. To start, we go to the layers panel and make sure that there is a white border around the layer mask thumbnail. Only click the layer mask thumb nail if there is not a white border. We then go to the tool bar and select the brush tool and in the options bar, select the brush picker to choose the size and hardness of the brush. By pressing D, we we can set the default colors of white and black in the tool bar. In order to switch colors, we can press X and this makes black the foreground color. We add black to the layer mask by painting over the image. As we said before, black hides the layer with the mask and this permits us to see the layer below which represents transparency.
White to reveal
By painting white to a layer mask it reveals the layer that has the mask in it. We start by pressing X so we can switch the foreground and background colors in the toolbar and white becomes the foreground color. And then we paint over the hidden areas of the image. By doing so, we add white to the layer mask and this brings back into view the areas of the masked layer.