Capture the Moment!

Here are all my posts on photography, covering techniques, trips, research, exhibitions, talks and workshops. Watch out for my latest article every Saturday.

I’ve also written dozens of articles for Expert Photography and Camera Reviews.

If you’d like to contribute a guest post on any aspect of photography, please email me at nick@nickdalephotography.com. My standard fee is £50 plus £10 for each dofollow link.

Note: Some blog posts contain affiliate links to Amazon.com and Amazon.co.uk. As an Amazon Associate, I earn from qualifying purchases.

A Lightroom Trick to Separate Subject from Background

Good enough for government work…

Photographs are flat, 2D images, but how can you make them appear three-dimensional? Inspired by a couple of videos by Matt Kloskowski and Steve Perry, here are a few Lightroom tricks to create depth by separating your subject from the background.

All these techniques are based on an understanding of the human eye, which is drawn to sharpness, contrast, colour and warmth. Using Lightroom’s AI masking with Auto Sync, you can quickly add those qualities to your subject and subtract them from the background across as many images as you like!

This is a real time-saver for me as I submit 100 images every week to all my stock agencies. Preparing each one individually would take too much time, so I can simply batch-edit them and check through them afterwards to see if I need to make any further changes.

Obviously, this doesn’t mean I don’t try to get everything right in camera, but it’s a useful tool to make the most of what you’ve got.

AI Masking

Lightroom introduced AI-powered masking in the October 2022 release of Lightroom Classic (version 12.0). The advantage is that you can now select the important elements in an image with just a couple of clicks.

To get to the masking menu, you just have to press ‘K’. That will automatically turn your cursor into a brush to ‘paint’ over the image to create a mask. If you’d rather use the AI functionality, you can click on Create New Mask in the floating box. That’ll bring up the four AI selection options:

  • Subject

  • Sky

  • Background

  • People

As well as those, you can choose to select things manually using another series of tools:

  • Objects (by painting over a particular area and letting Lightroom’s AI ‘guess’ where the object is)

  • Brush (by painting anywhere)

  • Linear Gradient (by creating a fall-off along a straight line—either horizontal, vertical or diagonal)

  • Radial Gradient (by creating a fall-off outside a circle or ellipse)

  • Color Range (by a specific colour or colours)

  • Luminance Range (by a chosen level of brightness)

  • Depth Range (by distance from the camera—but it’s only available on HEIC files captured with an iPhone in Portrait mode)

If you want to go straight to the masking tools, you can also hit Shift-W. This brings up icons for Subject, Sky and Background and a slightly different way of choosing the selection options:

  • Objects

  • Brush

  • Linear Gradient

  • Radial Gradient

  • Range (which expands to show Color, Luminance and Depth)

  • People (found automatically)

These are the basics of masking. Read on to find out how you can use them to separate your subject from the background and automate the process for batch editing.

Subject Selection

The first step in the process is to select the files you want to work with. In my case, these will be my 100 weekly submissions to stock agencies. Once you’ve done that, you can go to the masking menu (using ‘K’ or Shift-W) and toggle the Sync… button in the bottom right-hand corner of the Develop panel to Auto Sync. If you now select your subject in the active image, Lightroom will do the same in every single image you’ve selected—which means it takes a few seconds. Don’t worry if the selection isn’t perfect. You can fix it later.

The next job is to change the masking sliders to emphasise the subject. As I mentioned earlier, the eye is drawn to sharpness, contrast, colour and warmth, so you can add any or all of those to your subject mask. It’s up to you how far you go and which sliders you use, but subtlety and realism are important, so I’d start with +10 (or +0.10 for Exposure) rather than whacking everything up to 100! These are the main sliders for each attribute:

  • Sharpness: None if you use Sharpen or DeNoise AI in your workflow (otherwise Texture, Clarity, Sharpness and/or Noise sliders)

  • Contrast: All the Tone sliders (Exposure, Contrast, Highlights, Shadows, Whites and/or Blacks) and Dehaze

  • Colour: Saturation slider

  • Warmth: Tint slider (or perhaps Temp and Hue)

Once you’re happy with your changes, it’s a good idea to save them as a custom preset. Just click on the Custom label by Effect at the top of the masking panel, click Save Current Settings as New Preset…, give it a suitable name such as ‘Subject’ and click Create. You can then choose it from the Effect menu any time you like.

Now, before making changes to the background, it’s probably a good idea to check the subject selection in all your images. That’s because the best way of selecting the background is to use the Duplicate and Invert Mask command under the three-dot menu for the subject mask. If the subject selection isn’t right, the background selection won’t be either!

Background Selection

Once you’ve checked the subject masking for all your images, it’s time to make the opposite changes to the background. Everything you added to the subject needs to be subtracted from the background. That means taking away sharpness, contrast, colour and warmth.

To do that, click on the three-dot menu next to the subject mask in the floating masking controls box and select Duplicate and Invert Mask. This selects everything in the image apart from the subject. Again, if you’re working with a lot of images, Lightroom will take a few seconds to complete the task.

Once you’ve selected the background, you can go through the same process as you did for the subject—except in reverse. That means setting your chosen sliders to -10 (or -0.10) rather than +10 (or +0.10).

Again, you should probably save the settings as a custom preset in the same way as you did before in the Effect menu.

This time, you won’t have to check the subject selection, but it’s always worth going through every image individually to make sure you’re happy with the masking results. It’s easy to go a bit too far, and, of course, settings that worked for the active image won’t automatically work as well for the rest. How much time you spend on this step is up to you…!

This might also be a good chance to check your other settings for each file, such as white balance, geotags, keywords and other metadata. There’s a lot to do…!

Bonus Tip

If you want to tweak this process to make it less mechanical and more realistic, you can reduce the effect of the background mask by adding a radial filter. Once you’ve created the background mask, click on the three-dot menu and select Intersect Mask With… and then Radial Gradient.

You can then draw a circle or ellipse by clicking and dragging away from the centre of your subject. This means the effect of your changes to the background will be highest right next to the subject but then fall off as you reach the edges of the frame.

Laura BC offers a neat trick, which is to reduce the Dehaze slider on the Radial Gradient at an angle that matches the angle of the sun (see video). This brightens the background behind your subject, but it looks more realistic as it looks as if it happens naturally in the sunshine.

Verdict

Lightroom’s new masking tool is a real time-saver when it comes to polishing up your images—especially when using Auto Sync. It won’t always get you to a version you’re totally happy with, but it’s a good first step to adding depth and dimensionality.

It goes without saying that you should always try to do as much as possible in camera, but that shouldn’t stop you from using the power of AI to help you create separation between your subject and background.


If you’d like to order a framed print of one of my wildlife photographs, please visit the Prints page.

If you’d like to book a lesson or order an online photography course, please visit my Lessons and Courses pages.