Masking in Photoshop: Understanding Layer Masks and Clipping Masks

maskinginphotoshopMasking is one of the most powerful, yet misunderstood features in Photoshop. When used right, masks can be used to create very effective visual effects. From blending images to stylizing texts, there are hundreds of uses of masks in Photoshop.

Masking can be difficult to understand for beginners to Photoshop. Courses such as Photoshop 101 will give you a firm grounding in layers, masks, and common Photoshop features.

In this blog post, we will learn about the two types of masks in Photoshop: layer masks and clipping masks through some examples.

What are Masks in Photoshop?

The best way to understand Photoshop masks is to think of masks in real life. As Scooby-Doo and the gang has repeatedly shown us, masks can be used to hide or reveal what’s underneath. When you wear a mask, you essentially control your transparency, i.e. what and how much you choose to show. The same concept applies to masks in Photoshop.

There are two types of masks in Photoshop: layer masks and clipping masks. You’ll find that they are fairly similar in theory, but wildly different in application. Below, we’ll not only learn what these two masks are, but also learn how to use them.

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Understanding Layer Masks

Layer masks is one of Photoshop’s most useful features. The path to Photoshop mastery begins with grasping the power of layer masks.

A layer mask basically controls a layer’s transparency. It can only have monochromatic colors in grayscale, i.e. between white, black, and the various shades of gray in between. Adding a layer mask on top of an image allows you to control how much of that image is visible.

You’ll understand it a lot better once you see an example.

Layer Mask Example

Let’s suppose that we have these two images:

cat-in-grass

(Source)

 rover-002

(Source)

We want to merge them as quickly as possible without using tools like Eraser (see below on why you shouldn’t use erasers).

How do we do this?

Simple: layer masks.

Let’s follow along with a step by step review of the process:

1. We opened both the two images in separate Photoshop documents.

2. Since the cat image is smaller than the dog image, we moved it by pressing V on the keyboard and dragging it over to the dog image.

catanddog

3. We moved the cat image slightly to the left. Next, we applied a Layer Mask by clicking the layer mask button in the Layers panel.

layermask

The white rectangle that shows up next to the image thumbnail is the layer mask.

 whiterectangle

By default, every layer mask is colored white, which means that the image is 100% visible. If it were colored black, it would mean the image underneath was 0% visible. Try it out right now: ALT + Click on the layer mask thumbnail. A window with a white fill will pop-up. Fill it with black or gray color. ALT + Click on the thumbnail again.

Notice how the image visibility changes?

For example, here’s what happens when I fill the layer mask with a gray color (#7e7e7e):

dogcat

4. Our objective is to make only certain parts of the cat image visible. Since we know that filling in a layer mask with black makes the image underneath completely visible, we can use this to our advantage.

To do this, we’ll select the layer mask in the Layers panel (selected layers have a white box around them). Next, we will select black as our foreground color.

layerspanel

We will now choose the brush tool (or hit B on the keyboard) and paint roughly around the cat. (Pro Tip: Press the right or left square bracket to increase/decrease brush size).

This is what happens:

brushtool The brush erases the cat image and reveals the dog image underneath. Neat, right?

Now let’s decrease the brush size to erase away all but the cat from the image. We will zoom-in to get the finer details. We will also move it to the top of the image so that the top of the tail (which was cropped off in the original image) doesn’t look weird.

This is what our image looks like now:

decreasebrushsize

Almost done. The cat is still too big, so we need to reduce its size. We can do this by pressing CTRL + T and dragging the size bars until the cat looks the right size.

Here’s the final image:

finalimage

Not perfect by a long shot, but you should get the general idea how layer masks work.

“But”, you ask, “why didn’t we use the Erase tool to erase out unwanted parts of the image?”

Two reasons:

  • The eraser is a destructive process. Parts of the image once erased can never be retrieved.
  • Layer masks are far more flexible than erasers. Using the brush is just one way to use layer masks. As you will learn in courses like, layer masks can be used for many different effects.

So now that we understand the basics of layer masks, let’s dive into the other type of mask in Photoshop: clipping masks.

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Understanding Clipping Masks

Clipping masks work in the same way as layer masks, except that they don’t have the monochromatic grayscale color range. Instead, they borrow the transparency of the layer beneath them.

Don’t worry if you don’t get it at first. Clipping masks are nearly impossible to understand without an example.

For this example, let’s say we want to write some text which has this grass texture:

grasstexture

(Source)

Clipping Mask Example

1. Open your grass texture in a new document in Photoshop. Right click on the background layer in the Layers panel and select “Layer From Background”.

2. Create a new layer (CTRL + SHIFT + N) and enter your text.

grass2

3. Drag the grass texture layer above the text layer.

grass3

4. Now go to Layer Menu and select Create Clipping Mask. Alternatively, press CTRL + ALT + G.

Voila! Your text will now have the grass texture underneath.

grass4

5. Tidy up the image by adding a fill layer (Layer -> New Fill Layer -> Solid Color) and dragging it beneath the text layer.

grass5

So there you have it: a perfect use case of the powerful clipping mask tool. As you can imagine, there are many, many uses of this wonderful feature. You can learn more about clipping masks and layer masks in this course on Photoshop Selections and Masks.