There are a number of ways to change the background of an image using Photoshop, but one of our favorite approaches of compositing is to move the subject of the photo from one scene to another. In a new tutorial Anthony Morganti shares his tips for moving a subject into a new scene using the Quick Mask tool and iCloud Selection tools to bring their shadow along for a more realistic effect.
#1: Prep the Quick Mask tool
Change the settings on Photoshop’s Quick Mask tool to Selected Areas and change the Opacity to 100 percent.
#2 Select your Subject
Press the W key to activate Photoshop’s selection tools. From there use the dropdown menu and select iCloud to select the subject—using this option will typically give you a better selection than doing it manually. Once the subject has been selected you will likely need to make some refinements to the selected area. Click Select and Mask and then select your desired overlay view.
#3 Refine your Selection
You can continue to use the iCloud feature to start these refinements—it will give you options in the dropdown menu to refine hair. To make more precise refinements to your selection press R to activate the Refinement Edge Brush. Use this brush to paint in any additional refinements on your selection. Use the right and left bracket keys to easily change the size of your brush. Finally go to Output Settings and select Decontaminate Colors and output the selection to a new layer. A clipped out version of your subject will now exist on a separate layer. Later you will use this to composite onto a new background.
#4 Select the Shadow
Select your background layer and turn off the layer that you just created. Select the Channels tab, hold the Command key and click on the RGB channel. This will give you a selection of the highlights and mid tones in the image. Hit the Q key to then turn on Quick Mask mode. Next you will want to invert the selection. Improve the selection by bringing up Levels, and using the slider to refine the mask so that the majority of the mask color appears on the subject and the subject’s shadow. Turn off Quick Mask Mode by hitting the Q Key, and then use Command + J to get the shadow selection on its own layer.
#5 Move the Subject + Shadow to a New Scene
The subject and their shadow will now exist on individual layers, before you composite them into the new scene and combine them into a single layer. Click the V key to activate the Move function and then you can move the model into the new scene to create your composite.
#6 Adjust the Subject to Fit the New Scene
Use the Free Transform tool to adjust the size of the subject so that they fit into the new scene that you’ve placed them in.
#7 Adjust the Shadow to Match The Light Source
Right click while in Free Transform mode and select Flip Horizontal. This will ensure that the shadow your subject is casting matches the shadows being cast by other objects in the scene.