Adobe PhotoShop – Layer and Layer Mask Basics

By Megan P Galope

If you’re new to PhotoShop, layers can be a bit daunting. What exactly are they, anyway? Layers can be used in a multitude of ways, but I will just discuss the basics of how to use them to make general adjustments to photos.

First, what are layers are why are they useful? Layers are a non-destructive way to make adjustments to your image. They are useful because you can go back later and update and/or delete the adjustments you had made. For example, say you want to change the brightness/contrast of your image. One way to do that is to go to the Image menu, select Adjustments and then Brightness/Contrast. The problem with doing it this way is that you are directly making changes to your image (this is considered “destructive editing”) and you cannot go back later and re-adjust your edits. Layers solve both of these issues.

To create a layer, click on the “New Adjustment Layer” button (the half white, half dark circle) at the bottom of the Layers tab. Then choose the adjustment type you would like to make. Here we will choose Brightness/Contrast.

When you choose the adjustment type, you’ll see another layer appear in the Layers tab and the Properties box will appear for the adjustment type you chose. You can then make your adjustments. For this image, I’d like to darken the background and grass a bit and add some contrast.

The problem now is that the bear is too dark. Here is where layer masks come in handy. What I want to do is remove the layer adjustment for the bear only. You can do this by painting on the mask (the mask is the little white box in the Layers tab that is next to your adjustment). To “block out” your adjustments on part of the image, you will need to paint on the mask with a black brush. When it comes to layer masks, they say “white reveals and black conceals”. You can think of the mask as a stencil—the white parts of the mask are the holes in the stencil so the paint can come through.

To paint on the mask, first click on the mask (the white box in the Layers tab) and select the brush tool in the toolbar. Then make sure the selected color is black (at the bottom of the toolbar, make sure black is the foreground color—you can change this color by clicking on it and selecting black in the pop-up box). Change the size of the brush to what you need and start painting on the image where you want to remove your adjustments. If you don’t want to completely remove your adjustments but just tone them down a bit, then you can change the opacity in the brush properties toolbar at the top to a lower amount.

Once you’ve painted on the mask, you can see what you’ve done on the layer mask in the Layers tab.

And if you decide you’ve painted over too much, just change your brush color to white and paint it back in! If you want to update the original changes you made to brightness/contrast, double click on the circle icon next to the mask and it will bring up the Properties box so that you can edit your adjustments.


Megan P. Galope is a Photo Guide with Arizona Highways PhotoScapes.

Twitter = @megangalope