How to Blur the Background in Lightroom: A Complete Guide

If you want to give more emphasis to your subject, you must minimize the background. The best way to achieve this is in-camera; you can focus on the subject but pick a wide aperture and a long focal length for limited depth of field. The result is a sharp subject but a blurred, simplified background:

That is the ideal method. I’m going to teach you how to blur the background in Lightroom, but with the caveat that it is not the best way.

What if your image is sharp from front to back but the background now competes for attention? You didn’t think about it and made your shot with a smaller aperture, wide focal length, or both. Or perhaps you’re dealing with a smartphone image, where a small sensor size and a very short focal length almost always creates images with everything in focus.

If you failed to get a blurred background in-camera, your next best option is Photoshop – or another sophisticated editing program that supports layers, selections, and functions like gradients and Gaussian blur.

As for Lightroom: It’s a fair option. It will work, but using it to blur your background probably ought to be thought of as a “rescue mission.” I don’t want to discourage you – Lightroom often can produce a very acceptable blur – but I’d strongly encourage you to shoot multiple images during your photo session and vary the aperture if you think you might want to soften the background.

But all the coulda, woulda, and shoulda regrets over how you might have made a better in-camera capture don’t count when the session is over, the images are already made, and Lightroom is the only editing tool you have.

So let me show you how to blur the background in Lightroom.

Two major steps

There are two major things to consider when blurring the background in Lightroom:

• What area(s) you want blurred
• The kind and amount of blurring you want

The what and how of masking

In Photoshop, defining the area you want to work with is typically done with selections. There are a variety of tools to create selections, and once you’ve made them, you’ll typically see the “marching ants” – the animated dotted-line border that defines your selected area.

But in Lightroom, there are no selections, and you’ll never see the ants. Instead, Lightroom uses what it calls “masks” to allow you to select areas where you want effects applied.

There are three local adjustment tools you can use in Lightroom to select areas and apply masks:

• The Adjustment Brush
• The Graduated Filter
• The Radial Filter

Blurring the background with a Graduated Filter and the filter brush

It’s probably best to think of your filter brush more as an airbrush than a paintbrush. There are four settings you can use to control its application:

• Size: Changes the size of the brush. Roll the mouse wheel, use the left and right bracket keys, or use the slider.
• Feather: Changes how hard the edge of the brush is and how rapidly the effect falls off. Use Shift while rolling the mouse wheel, Shift and the bracket keys together, or the Feather slider.
• Flow: Controls how quickly the effect is applied with each stroke of the brush. Use the slider to adjust the flow, or with the brush tool selected, change the flow with the number keys on the keyboard. Using multiple strokes will build up the effect.
• Density: Controls the maximum opacity of the brush effect. For example, if the Flow was at 100 but the Density was at 50, one stroke of the brush would apply the effect at 50% opacity.

It is possible to simply select the Adjustment Brush, drag the sharpness slider all the way down (“reverse sharpening”), and start painting away on your image, watching the painted sections become more blurred. (You are still creating a mask this way, but you will not see it unless you turn on the Mask Overlay).

The Adjustment Brush method might work fine if you don’t mind being imprecise about how finely the blur is applied, but it is not the best method for finer work.

Radial Filter

The Radial Filter has a shape that is restricted to circles and ovals. The effect radiates out from the center of the spot where it is applied. You can control its size, feathering, and orientation.

Using the Invert checkbox, you can also control whether the filter effect occurs outside the oval (the default), or inside the oval (if the Invert box is checked).

The Overlay option

Being able to see where you’ve applied a mask makes things easier, so turning on the Mask Overlay option is a good idea. This can be done by either checking the box at the bottom of the screen labeled Show Selected Mask Overlay or by tapping the “O” key on your keyboard.

You can cycle through various overlay colors (which can help to make your mask stand out over different photo colors) by using Shift + O.

Modifying masks

Though the Adjustment Brush, Radial Filter, and Graduated Filter are the only tools for applying masks, there are other tools for modifying them.

• Auto Mask – Checking this box while working with a brush will help the brush find edges in your image and can make masking much easier.
• Erase – You can use the Adjustment Brush to paint on a mask. When doing so, you will see a “+” symbol at the center of the brush. Clicking the Erase option will change the symbol at the center of the brush to a “-” symbol so that you can erase portions of the mask you already painted on. You can also easily switch from painting to erasing by holding down the Alt/Option key.
• You can add or subtract from Graduated Filter or Radial Filter masks with the filter brush tool. If you are working with a Graduated or Radial Filter mask, you will see the word “Brush” appear to the right of the word “Mask.” Important: This is a different brush than the Adjustment Brush tool. It will allow you to add to or subtract from your existing Graduated Filter or Radial Filter mask.

Range masking

Lightroom has recently added what is called the Range Mask.

With Range Masking, you still apply an initial mask using the three tools mentioned above (the Adjustment Brush, the Radial Filter, and the Graduated Filter). But by turning on Range Masking, you can control more specifically where the mask is applied.

The Luminance Range Mask will allow you to selectively apply a mask to a range of luminance (brightness) in the photo, while Color Range Masking allows the mask to be applied to a range of color (hue). Being proficient with the Range Mask will serve you well as you become a more skilled Lightroom editor.

Learning how to create a mask to work with the areas you want is the most important part of how to blur the background in Lightroom. Take time to carefully apply and fine-tune your masks. How convincing your final image will be is highly dependent on the careful application of your mask.

Creating the blur

Creating your masks will determine where your blurring effect is applied. It’s the more time-consuming and critical step.

But these next steps will determine how the blur looks.

Let’s say you have a person in your foreground as the main subject. You want them to be sharp, but you’d like to blur the background. Using the masking tools and techniques I’ve outlined above, here’s how I’d approach the image:

1. Drag a Graduated Filter across the image so the entire scene is masked.
2. Use the filter brush tool (the one that’s part of the Graduated Filter) to fine-tune the mask, erasing portions over the subject, adding back as needed, and perhaps also using the Auto Mask feature to help you better mask near the edges.
3. Now, with your Graduated Filter selected, drag the Sharpness slider down, perhaps all the way to the left.
4. See if dragging down the Clarity slider a bit helps achieve the blur you want. Use this more sparingly than the Sharpness slider as it can create a strange look if applied too strongly.
5. Play with the other sliders to see what effect they might have. Remember that each slider will only affect the masked area.

Double down on the blur

You might find that even if you drag your Sharpness or Clarity sliders all the way to the left, you still aren’t getting the amount of blur you’d like. Time to double down.

Once you’ve added the sharpening or clarity effect, right-click the pin and hit Duplicate. A copy of the adjustments will be applied on top of the existing adjustments, and the blur will be multiplied.

Still not enough? Repeat and duplicate again. You can make as many duplicates as you like, slowly building up the effect.

When you blur the background in Lightroom, less is more

Let’s come back around to what I said at the beginning of this article:

Using Lightroom to blur your background is not the best way to achieve the look you’re after. Softening details with editing is a bit of fakery and cannot begin to truly reproduce the kind of bokeh blur achieved with a lens.

So instead of creating something that is immediately obvious and calls attention to itself, be subtle. If an untrained observer would say, “This looks like an editing effect,” you’ve failed.

Spend whatever time it takes to create and refine your masks so that it’s not obvious where the edge is. Consider the different parts of the scene that should – and shouldn’t! – be blurred.

Then be sparing in your application of reverse sharpness and clarity. It’s always a good practice to take a break after an editing session to give your eyes a rest, then look at your image again later. You might even ask someone else to view the image. (They should not be able to tell that anything was doctored.)

How to blur the background in Lightroom: final words

In teaching you how to blur the background in Lightroom, I want you to be successful with your editing and make beautiful images.

So test out the techniques I’ve shared. And if you get good results, post some of your before and after images in the comments below!