When I first dove into the magical world of Photoshop, I was intimidated!
All of the buttons and options overwhelmed me to the point that I would open the software and then close it a few minutes later. How would I ever learn enough to create professional edits and composites? After managing my time better, being patient with myself, and with a bit of courage, I devoted some free time to tackling the software. I watched videos, wrote notes from tutorials, practiced with images, and eventually found myself building the skills I needed to carry out the edits I wanted. One of the first and most important things I familiarized myself with was layer masks.
What is a layer mask?
A layer mask is a tool that gives you control of each layer you are working with. It allows you to take a single layer and modify specific areas of the image, rather than global changes on the entire layer.
Let's say you open a new layer to adjust brightness or exposure on your image. Maybe you need to bump up the exposure a few stops only on your subject's face? Or maybe you ran a Photoshop action but only want it to affect only certain areas of your image? A layer mask gives you the flexibility to do this.
How do you use a layer mask?
First, open the image you are working with in Photoshop. For this basic tutorial, I'm using a stock image from Pexels, which is a great resource for open source stock.
Once you have the image opened, create a new fill adjustment layer. This can be done by clicking on the half filled circle located at the bottom of your layers panel, as shown circled in red below.
Once you click on the fill/adjustment layer drop-down arrow, you will get a window of adjustment options to choose from.
For this basic tutorial I'm going to do an exposure adjustment layer. I bumped the exposure up to around +2 in the properties panel. The entire image is much brighter now! Now we can move on to learning about adding a layer mask to this exposure adjustment layer.
When you create a new fill or adjustment layer, it automatically adds a layer mask to it. If you don't have a layer mask, it's easy to add one. Make sure the layer you are working on is highlighted in blue, then click on the rectangle icon at the bottom of the layers panel (I've circled this in red below).
Once you click on the layer mask icon, you will see there is now a white box in the exposure layer.
A key phrase to keep in mind when working with layer masks is "white reveals, black conceals". Since our layer mask is white, this means the adjustment is revealed or showing on the image we are working with. To paint black on a layer mask means you're hiding that part of the adjustment.
To keep this simple, we are going to leave our white layer mask as it - painting black to conceal the exposure adjustment we just made.
Now lets “brush away”, or remove, some of the exposure from half of the image. To do this, select the brush tool from the toolbar, leaving opacity at 100% just to get the full effect. Remember, we are wanting to hide the adjustment from part of the image, so we'll need a black brush.
You will also notice that the white layer mask in the adjustment layer is now half black, showing where we hid the adjusments. If you want to bring part of the exposure back in that area, just switch your brush from black to white and paint the adjustment back in. Remember "white reveals, black conceals"!
Now that we have our white layer mask and black brush ready to go, we can paint over the areas we want to remove the adjustment from. As mentioned earlier, I'm leaving my brush opacity at 100% just so that the changes are clearly visible. Once you become more familiar with layer masks, you can play around with adjusting the opacity of the brush to choose to what degree you want to conceal/hide. If my opacity was set to 10%, the changes would be much more subtle.
TIP: You can invert the layer at the bottom of your properties panel to reverse the effect of what your mask conceals and reveals.
As you can see below, working at 100% opacity with my brush, I have completely removed the exposure adjustment over the right half of my image by brushing over the area.