What Is Image Masking?
No matter what photo editing program you’re working in, image masking is an important part of making selective adjustments. Although each program has a slightly different way of masking, the purpose remains the same. By applying a mask to an image or adjustment layer, you can better control where it will be applied in your image. That way, you can easily target specific areas of your image for a more enhanced edit.
Depending on which photo editing program you use, there are many types of image masking options. In this article, you’ll learn the different types and the purpose of image masking in post-processing.
When you are “masking” an image while photo editing, it means you’re limiting where a certain layer or adjustment is visible. A mask allows you to adjust a certain portion of your image while leaving the rest completely untouched. For example, you could use a mask to brighten your subject while leaving the background unedited. Simply put, masking adjustments give you precise control of how and where photo editing adjustments take place.
Now that you understand the very basics of image masking let’s discuss it more in-depth. Below you’ll learn more about the uses of image masking, how it works in different programs, and how to use it in your own workflow!
What Is Meant By “Masking” An Image?
Image masking is using masks or selective adjustments to isolate where an adjustment is taking place. This looks slightly different depending on which photo editing program you use, but the result is the same. For example, when masking in Photoshop, you are working with a dedicated layer mask. Here you can make any type of selective adjustment, using black, white, or grey, to choose an adjustment’s transparency.
In the images below, you can see three different versions of color in the sky. By masking the solid color layer, I can choose where it’s visible in the photo (the sky in this case) and how transparent that adjustment is. Notice how in each version of the mask, the solid color becomes more and more visible. This is directly caused by creating different brush and opacity adjustments to the layer mask.
Photoshop is one of the best examples of a post-processing software that uses masks as an integral part of the editing workflow. You can apply masks to any type of layer, giving you infinite control over your image. We’ll discuss this more in-depth later on in the post, but for now, let’s talk about another type of image masking you’ll find.
The other example of image masking is with selective adjustments. Rather than creating a layer mask that you can view separate from your layer, selective adjustments are only visible on your photo directly. In Lightroom, there are a series of selective adjustments that you can use to isolate your edits.
However, unlike Photoshop, these selective adjustments can only be used for exposure, contrast, or color adjustments. Since there aren’t any layers, it’s impossible to use these masks to blend multiple photos or remove backgrounds from an image.
No matter what editing program you’re working in, you’ll come across masks in the form of dedicated layer masks like in Photoshop or spot adjustments like in Lightroom. Both options serve the same purpose, but the way Photoshop uses masks in photo editing gives you more options.
Types Of Image Masking In Post-Processing
There are a variety of image masking techniques depending on which program you use. Although there are other programs out there, the masking techniques found in Lightroom or Photoshop can be found in other editing programs as well.
Since it’s all transferrable, I’ll only focus on image masking in relation to these two programs. Just remember that similar ideas apply to other programs such as Luminar or Capture One as well.
– Masking Adjustments In Photoshop
Below are 5 of the common masking types found in Photoshop. Since this program is layer-based editing software, it uses dedicated layer masks for each layer. You will find similar masking options in other programs that work with layers.
1. Alpha Masks
The first type of mask in Photoshop is called an Alpha Mask. This masking technique uses the color channels in your image to separate certain edges based on their contrast. Using this contrast to convert your image into black and white, you can easily mask out an entire background or select your subject.
With Alpha Masks, you can apply complicated masking adjustments with ease. For example, you could select the complex edges of someone’s hair or perfectly cut out all the leaves on a tree.
Many advanced photo editors and photographers will use Alpha Masks to make accurate masks around edges that wouldn’t be possible to select otherwise. You can learn more about Alpha Channels (aka Channels) and how they work in this post.
2. Clipping Masks
Clipping masks let you isolate where a layer is visible by restricting it to the confines of another layer. For example, if you wanted to fill a text layer with an image in Photoshop, you could apply a clipping mask between the image and the text. The result is that your image is only visible within your text layer.
This type of masking adjustment can be used in a wide array of applications. The options are limitless from selective adjustments onto certain layers, creating collages, or graphic design purposes.
With this type of masking, you don’t need to manually make any type of selection beforehand. Instead, it uses the shape of one layer to refine the visible area of another.
3. Standard Layer Masking
The most basic way of masking an image in Photoshop is using the brush tool and manually painting over your image. Using black (100% invisible) and white (100% visible), you can paint anywhere on your photo to isolate its transparency. For example, if you only wanted to darken the sky in an image, you could use this technique by creating a new brightness adjustment layer and refine the mask to only be visible in the sky.
This is the most common type of masking done in Photoshop and is something you’ll use in every image you work on. It provides a simple and effective way of choosing exactly where an adjustment or layer is visible—all with the help of your brush tool.
4. Vector Masks
To understand the value of vector masks, it’s first important to know the difference between a rasterized layer and a vector layer. Vector masks are used in graphic design as a way to maintain sharper edges in your image. Rather than creating pixel-based masks, vector masks are resolution-independent paths created with anchor points via the pen tool or shape tool.
If you are working with text or graphics, using vector masks maintains a sharper edge when exporting files as PNG or SVG files. For standard photo editing and selective adjustments, they are not as commonly used. However, they are still an important part of masking in Photoshop.
5. Gradient Masks
The final type of mask in Photoshop are gradient masks. These are similar to standard layer masks, except using a gradient adjustment rather than the brush tool to refine your layer mask. This offers a unique advantage when blending adjustments since you can get a clean transition between visibility and transparency. For example, you could make part of your layer transparent or help blend an adjustment near the edge of your photo.
Gradient masks are created by applying a Gradient Tool adjustment onto a layer mask. By using black and white in your gradient, you can create seamless transitions on a layer mask. Just take a look at the images below using a gradient mask to blend a layer into the image to see how valuable these masks can be.
– Masking Adjustments In Lightroom
In Lightroom, you don’t make adjustments with layers or individual masks. Instead, Lightroom uses selective adjustments that apply masks directly onto a photo. This type of masking is commonly found in any program that doesn’t use layers.
1. Selective Adjustment Brush Masks
The primary method of masking in Lightroom is with the Selective Adjustment Brush. This tool lets you paint a selection area onto your photo, which you can use to isolate specific adjustments. Although it is called “selective” adjustments, it’s simply another form of masking.
With the selective adjustment brush, you can adjust your brush’s hardness, flow, and opacity to help blend in adjustments. This tool is perfect for making more precise adjustments without affecting any of the surrounding areas.
2. Gradient Filter Masks
Like the selective adjustment brush, the gradient filter applies a mask to your image, but in the form of a gradient rather than a selective brush. This offers a huge advantage for making well-blended exposure, contrast, and color adjustments to any part of your photo. When you want to darken the edges of an image or selectively adjust the sky, gradient filter masks are a perfect option.
In Lightroom, Gradient filters transition an adjustment from 100% visible to 100% transparent. In the example below, you can see how the brightness adjustment is extremely noticeable on one half of the gradient while completely transparent on the other.
3. Radial Filter Masks
Radial Filter Masks let you create gradient styled masks, except in a circular shape. This masking method is perfect for drawing attention to a certain area of your photo or brightening around your subject.
With this masking adjustment, you can affect the inner or outer part of the radial mask. That way, you have more control and added options for how your mask affects your image.
4. Range Masks
Range masks are an incredibly powerful tool in Lightroom that allows you to refine selective adjustment masks based on color or luminance values. The advantage of this is you can make more accurate adjustments without accidentally affecting surrounding areas. This is a huge win for isolating an adjustment and getting a more specific edit on your image. You can learn how to use Range Masks in this video tutorial.
5. Auto Masks
Auto Masks are another feature that can be used alongside the selective adjustment brush. Rather than letting your adjustment spill over edges, auto mask samples the color and exposure values near your brush to refine your mask. If you were to mask along the edge of a building or mountain peaks, an auto mask would ensure your selection doesn’t spill over the edges.
The video tutorial below outlines the unique advantages that Auto Masking offers in Lightroom:
What Are Masks Used For In Photo Editing?
Masks are used for controlling where an editing adjustment takes place in a photo. You can use them to refine your adjustment along a specific edge or make certain sections of an image completely transparent.
There are a wide array of things masking can be used for in photo editing, such as:
- Removing Backgrounds
- Selectively Applying Adjustments
- Blending Multiple Images
- Confining An Image Into A Shape
- Adding Transparency To An Image
Without masking while photo editing, it would be impossible to make certain areas of your photo pop. For example, if your RAW image has a brighter background than foreground, it would be difficult to apply the same editing adjustments to both areas. Since the foreground is so dark, it requires different adjustments than the brighter background.
Using image masking, you could easily target the darker areas while leaving the brighter areas of your photo untouched.
After using different masks, you end up with a more professional look and well-balanced edit than what would be possible to create without.
How Do You Mask A Picture?
Now that you know what image masking in post-processing is all about, how exactly do you mask an image? Since we have been discussing image masking in Photoshop and Lightroom so far, let’s go through a masking example in each program.
– How To Mask In Photoshop
For this example, we’ll go over a simple masking technique to blend two different images. Using a layer mask and the brush tool, you can quickly blend a new sky into your image.
Step 1: Create A New Layer Mask On Your Layer
Before you can make any selective masking adjustment in Photoshop, you need to create a layer mask. By selecting the layer you want to mask, click on the layer mask icon at the bottom of your Layers Panel.
By default, your new layer mask will be set to white, which means everything is visible. For the next step, you can paint black onto the mask to create transparency.
Step 2: Adjust Your Layer Mask With A Black Brush
Start by selecting the brush tool from your toolbar.
Then make sure your foreground color is set to black. In the world of layer masks, black is 100% transparent, which means painting it onto your white layer mask will make sections of the layer invisible.
Click on your layer mask to ensure it’s selected. That way, all the brush adjustments you make on your canvas will be applied to the mask.
Now begin painting over the areas of the layer you want to become invisible.
Step 3: Refine Your Layer Mask To Blend Your Adjustment
Continue painting over the areas of your layer that you want to make invisible. If need be, you can adjust your brush settings to get different results. I would recommend using a soft round brush for most masking adjustments in Photoshop.
Looking at the layer mask, you can see how there is black painted over the white. This indicates where your layer is visible (white) or transparent (black).
After going through and masking out all the required areas, the sky has been blended into the image in no time.
These same steps would apply to any selective adjustment or layer you work with in Photoshop. If you are looking to use masks to cut out images, check out this post sharing the 5 best methods.
– How To Mask In Lightroom
Unlike Photoshop, Lightroom doesn’t allow you to make parts of an image transparent. Instead, it uses masks to isolate certain photo editing adjustments in your image. To highlight these uses, let’s go through an example where we selectively brighten the subject in a photo.
Step 1: Choose A Selective Adjustment
As you learned earlier, there are a series of masking options in Lightroom. To keep things simple, I’ll use the selective adjustment brush to create my mask.
With the adjustment brush tool selected, I can further edit the brush settings depending on how I’d like the mask to look. Since I want to make a general mask around the person in my image, I’ll just use a soft feather.
Step 2: Create Your Mask
Now that the tool settings are in order, it’s time to create the mask. By painting over the person, the adjustment brush will begin to create a mask. By default, you won’t be able to see the masking area; however, you can press O to make it visible.
The red highlight you see indicates your masking area. Anything inside of this red highlight will be included in your adjustments.
If you accidentally mask over an area you don’t want to affect, you can press Alt or Option to switch to your eraser. By going back and forth between adding and subtracting from your mask, you can refine it perfectly to any edge.
Step 3: Apply Selective Adjustments To The Masked Area
With your masking complete, all that’s left is to apply your adjustments to the masked area. In Lightroom, a new settings bar will appear whenever you make a selective adjustment. Here you can change the color, contrast, and exposure, but those adjustments will only be visible in the masked area.
Since I want to brighten the person, I’ll boost the exposure slider just a little.
Now the person has been brightened, while the rest of the photo remains untouched!
You can use this masking technique in Lightroom for a wide array of adjustments. Better yet, you can create as many selective masking adjustments as you need on an image. Rather than being visible in a layers panel like Photoshop, each selective adjustment will be represented by a little grey dot on your photo.
Now you know what image masking is in post-processing and how it works to change the way you edit photos. Masking is an essential part of photo editing, and without it, it would be nearly impossible to get the stylized edits you’re looking for.
Any intermediate to professional level photo editing program will offer these types of adjustments. Although we only discussed masking in terms of Photoshop and Lightroom, the same idea applies across all other photo editing programs. By keeping these techniques and ideas in mind, you’re ready to apply kick-butt edits to your photos in any program!
– Brendan 🙂