Compositing one image onto another is a pretty regular task for Photoshop users. The tools Photoshop has make that task quite an easy one to accomplish, but not necessarily one that is accomplished well.
One of the key elements any Designer or Photographer can use to make a composite image look more true is the images shadows. Get them right and the jobs well on the way, get them wrong and it’s going to be obvious. Miss them out completely and your up for a place in a Photoshop Disasters Blog somewhere.
In this article I am going to introduce you to a simple yet effective method to add shadows to a composited image.
Select the image that is to be composited. Here, I have selected an image of someone running. With the Magnetic Lasso tool, click around the object you want to keep. When done, select Layer > Layer Mask > Reveal Selection or press the Add Layer Mask button. To tidy up the mask, choose Select > Refine Mask (Option-Command-R). Try to make it as neat an edge as possible by changing the Smooth and Feather values.
Drag the masked image onto the Background image to create a composited image.
Use Free Transform (Command-T) to size the image to scale. If the image looks too sharp for the background, which it probably will, open the Properties Panel and set the Masks Feather to perhaps 0.2/0.3 px. It should look a little softer.
Next go to Image > Adjustments > Match Color. Use this feature to make the colors of the masked layer better match the Background.
Set the Source: to the original Background file, and the Layer: to Layer 1. Use the Image Options such as Luminance, Color Intensity and Fade to refine the color match until you are satisfied they match, and appear to share the same light source.
Add a new layer to the Layers Panel (Shift-Command-N) and name it “Shadow”.
Drag the layer between the background and Mask layers like so.
Keep the Shadow Layer Selected, hold down the Command key and click on the Mask Thumbnail on the layer above.
This will re-load the selection that was used to create the mask.
Fill the selection on the Shadows layer (Shift-F5).
Choose 50% Grey with a Normal Blending Mode and 100% Opacity. Then press Command - D to deselect.
Choose Edit > Transform > Distort to create the illusion of the shadow being cast. Start by moving the Anchor Point to the position where the shadow meets the subject. In my case thats at the sole of the foot connecting with the ground.
Drag the position of the upper left and right points of the transformation editor until your shadow fits in with the image. TIP: Use the shadows that are already on the Background as a guide.
Change the Blend Mode of the Shadow layer to Color Burn.
Some people prefer Multiply, but I like the Color Burn effect.
Shadows are a little denser closer to the subject. We can do the same using the Burn Tool O. Set the Burn Tool to Hardness: 20%, Range: Shadow and Exposure: 50%.
Use the Burn Tool to gently darken the Shadow closer to the subject, making it appear a little denser.
Lastly, to create a sense of distance, and also to create the illusion of ambient light, apply a gentle Blur effect to the Shadow layer.
I’ve added a Gaussian Blur set to 1.9 pixels. You might also find that a small adjustment to the Opacity of the Shadow layer helps complete the look. I’ve chosen Opacity 76%.
And there you have it, a simple yet effective way to create shadows on a composited image.
David Smith is Scotland's most qualified Apple and Adobe certified trainer. Having completed his education at Edinburgh College of Art's BAFTA winning Film School, David moved straight into TV production, first as a Vision Mixer then quickly becoming, at the age of just 24, a director of live TV studio productions. In 2001 he moved into Higher Education where he became a lecturer in TV Production, specializing in post-production and live studio production. During this time, and working with the support of the BBC, Channel 4 and independent production companies, David was instrumental in the design, development and implementation of industry-approved vocational courses across Scotland's Colleges. In 2006, after working closely with Apple Computers to create a unique multimedia studio for education at the Music and Media Centre in Perth, David became Scotland's first Apple-Certified Trainer for Pro Apps. This led on to David forming the first Apple Authorized Training Centre for Education, north of Manchester. In 2008 David made the move to full time training and joined the ranks at Academy Class, Ltd. where he continues to train industry professionals as a certified trainer across the Adobe Creative Suite and Apple Pro Apps range.