Advanced Editing

Contrast masking

Written by Gail Bjork

Our step-by-step Contrast Masking tutorial demonstrate how to bring out detail in underexposed areas of an image.

Contrast masking is a useful image editing technique for adjusting the brightness and contrast in an image. It brings out more detail in the underexposed areas of a photo.

Original image

Original image

Contrast masking applied

Contrast masking applied

When to use contrast masking

Use contrast masking when the main subject in a photo is dark. Dark areas that show little or no detail are often a consequence of backlighting. Contrast masking inverts the dark and light in a photo to reveal more detail in underexposed areas.

Contrast masking-tutorial

How to apply a contrast mask in Photoshop

1. Open photo in an editing program that supports layers.

2. Duplicate the background layer.

3. Desaturate the new layer.

Original image

Image menu > Adjustments > Desaturate

4. Invert the layer.

Invert layer
Image menu > Adjustments > Invert

5. Apply a Gaussian Blur.

Apply blur
Filter menu > Blur > Gaussian Blur (set at a radius between 20 and 30 pixels).

Adjustments may need to be made to the amount of Gaussian blur used to avoid a halo effect where bright and dark areas meet.

6. Select Overlay from the layers palette.

Overlay

Once the contrast mask is applied, its intensity can be adjusted by changing the opacity of the layer. You can also fine tune by erasing portions of the mask. Do any additional editing, such as sharpening, before saving the image.

See larger view of final image

Note: Newer versions of Photoshop CS and Photoshop Elements have a Shadow/Highlight command, which produces results like Contrast Masking. The Shadow/Highlights command is easier to use and allows for greater adjustments.

Related reading: High Dynamic Range photography and software

About the author

Gail Bjork

Gail Bjork, who is passionate about digital photography, is the owner and editor of Digicamhelp.Gail is the author of three illustrated ebooks about digital photography. A number of her photos and digital photography related articles appear at other websites.In 2006, a series of her photos, People in the Louvre, were exhibited at the Underground Photo Gallery
in Iisalmi Finland. Eight of her photos taken in the Florida scrub are on permanent exhibition at Parrish Medical Center in Titusville, Florida.Gail served twelve years as an elected member of The School Board of Palm Beach County, Florida, one of the largest school districts in the U.S. She has also been the editor of a small town newspaper and a free-lance writer. Gail and her husband owned and ran several small businesses.