Some useful things you can do with masks is brighten/darken a certain part of an image (for example, someone’s face), fade the edges of an image, and place an image within text.
A layer mask allows you to control the visibility of a layer. You can use a layer mask to selectively show a part of a layer without modifying the original layer; it merely hides, or “masks”, the original layer. You can delete or disable a layer mask, and the original layer will still be there. You can use layer masks on both images and adjustment layers.
Brightening/Darkening Part of an Image
Say we have this photo of Morgan Spurlock and we want to brighten his face.
If we use an adjustment layer (I chose to use Curves), you can see that there is already a layer mask because there is a rectangle to the right of the chain that says “Layer mask thumbnail” when you hover. The chain links the layer mask to the layer, and unlinking will allow you to move the image or the mask around separately. This is not particularly useful in this case, but it can be.
I have selected Layer > New Adjustment Layer > Curves. A grid will show up with a curve that you can modify to find the look you are looking for. When working with layer masks, whatever is black on the layer mask will be hidden and whatever is white will show. The shades of grey in between allow varying degrees of transparency. By default the layer mask is white, so I have gone ahead and filled it with black in order to hide the entire Curves layer.
Then by using the brush tool, you can make part of the adjustment layer visible. You can see that my Curves layer now has a portion of white in it and Spurlock’s face is now brightened.
Then by using the brush tool, you can make part of the adjustment layer visible. You can see that my Curves layer now has a portion of white in it and Spurlock’s face is now brightened.
Fading the Edges of an Image
Layer masks also come in handy when you just want to blend an edge of image, for example, into a solid color.
So let’s revisit the Spurlock photo. First, I created a layer underneath the photo and filled it with black. You can go to Layer > New Fill Layer > Solid Color, or create a new layer and fill it. Then, at the bottom of the layers panel, there are seven icons. The third one is a rectangle with a circle on it, and this creates a new layer mask.
Now click on the new layer mask, the rectangle to the right of the chain. Click on the gradient tool and click on your starting point. You can hold down shift to keep the gradient tool vertically or horizontally exact. Then click on the ending point. Now our photo blends into the black background.
Image Within Text
A clipping mask allows you to mask a layer with the layers above it. If I have some text and I want to fill it with an image instead of just a solid color, I can use a clipping mask.
Let’s use the Morgan Spurlock image again. Our goal is to fill text with the image.
Create a new text layer and place it under the image. Right click on the layer and select “Create Clipping Mask.”
And that’s it! You can move around the image and resize as you see fit.
