Layer Mask Basics in Adobe Photoshop
By Linda Sattgast
A layer mask is an amazing tool that allows you to edit your photos non-destructively.
- A layer mask is accessed and used in the Layers panel. If you don’t see the Layers panel, in the Menu Bar, choose Window > Layers.
- The purpose of a mask is to hide part of a layer, so by that definition, you’ll normally have at least two layers. I added a second layer of some texture. The texture was created by taking a photo of an old wooden clipboard. You can easily photograph something similar to use with your photos.
- My plan was to change the blend mode of the texture layer to create an artistic look on my photo, but first let’s talk about layer masks.
White, Black, and Gray on a Mask
- Click on the Add Layer Mask icon on the Layers panel. A second thumbnail filled with white will appear on the layer, and nothing will change on your photo or document. That’s because white on the layer mask reveals everything on that layer. So when we’re using layer masks, that’s why we say “White Reveals.”
- The opposite of that statement is that “Back Conceals.” In the Menu Bar, choose Edit > Fill. When the dialog box comes up, open the Contents menu and choose Black. The Blending Mode should be Normal and the Opacity 100%. Click OK. This hides the entire layer. So, again, white reveals what’s on the layer and black conceals what’s on the layer.
- What does gray do? To find out, in the Menu Bar choose Edit > Fill Layer. Choose 50% Gray and leave all the other settings the same. Click OK. This makes the layer semi-transparent.
Layer Mask Principles
Here’s what we’ve learned so far:
- Wherever the mask is completely white, the layer will be revealed.
- Wherever the mask is completely black, the layer will be concealed.
- Anything in between black and white—in other words, gray—will partially reveal the layer. How much? That depends on how light or dark the gray is. The darker the gray, the more it hides the layer and vice versa.
Most of the time you won’t be filling the mask with black or white or gray. Most of the time you’ll be painting with white or black or gray using the Brush tool in conjunction with the Color Chips.
Change the Blend Mode
- Make sure the top texture layer is the active layer in the Layers panel.
- Change the blend mode at the top of the Layers panel from Normal to Color Burn.
- If the effect is a bit strong, reduce the opacity of the layer. (I reduced mine to 50%.)
- If the blended texture looks good over part of the photo, but it’s too much on other parts, use a layer mask to hide part of the layer.
- In the Layers panel, click on the Add Layer Mask icon.
- Get the Brush tool. In Tool Options open the Brush Preset Picker and choose a soft brush. The Mode should be normal and the Opacity and Fill should be 100%.
- Make sure the Foreground Color Chip is black. If it isn’t black, click on the curved arrows to switch colors, or press the letter X to switch the Color Chips.
- On your photo, brush wherever you don’t want the texture to appear. Wherever I brush with black I conceal the blended texture layer, because black conceals.
- Switch the Foreground Color Chip to white by pressing the letter X. Remember that white reveals. I wanted to reveal some of the texture, but only a little.
- To get the effect of gray on the mask, reduce the Opacity of your brush and brush on your photo. (I reduced my brush opacity to 30%.) This will bring reveal more of the texture layer wherever I paint.
- When you paint with a lower opacity brush, the more you paint over the same area, the more the texture layer is revealed.
Viewing a Layer Mask
It can be helpful to see what your mask actually looks like to understand what is going on behind the scenes.
- To view your mask, press Alt (Mac: Opt) and click on the mask thumbnail in the Layers panel. The white on the mask completely reveals the texture layer. The black on the mask completely conceals the texture layer, and the gray makes the layer partially visible.
- Painting on a mask allows you to be in charge of how much of the layer is visible.
- To hide the mask use the same shortcut: Press Alt (Mac: Opt) and click on the layer mask thumbnail.
Once you get the hang of using layer masks, you’ll be amazed at the number of ways it can help you create special effects!