Brightening exposure in darker photos is an easy adjustment to make in post-processing. This tutorial demonstrates methods for properly correcting underexposure, including how to identify problem areas with missing detail, balance the color saturation in adjusted tones, and more.
Photos: Halftone Studios
What is Underexposure?
The term ‘underexposed’ refers to an image that captured too little light. This technique can be used for a pleasing effect to intensify the color saturation in a sunset, but it normally refers to an image that is darker than it should be. Extreme amounts of underexposure will result in loss of image detail, especially in shadow areas. Shadows in underexposed photos are often blocked-up, meaning the darker tones are muddy and indistinguishable from each other.
The image format can make a difference in the amount of exposure you can compensate for when post processing. RAW is the best format for correcting underexposure because RAW images contain the most image data, which gives more latitude to make adjustments.
How to Fix Underexposed Photos
Exposure adjustments are the most common adjustments made during post-processing. The Basic panel is where you’ll find the Exposure slider, along with sliders for adjusting different tones in your photo.
Exposure controls the overall brightness of the photo. When editing, this is usually the first slider to adjust. Brightening the whole image will reduce detail in highlight tones, so closely monitor the highlights when increasing this slider.
Shadows controls the darker areas of the image. When you’re missing image detail in the darkest areas of an image, or when the shadows appear to block up into a mass of dark tones, adjust this slider.
Blacks controls the darkest tones in the image. Dial-in this slider after making adjustments to the other two sliders mentioned. In case of clipping, where detail is missing in the darkest parts of the original RAW image, increase this slider to the point just before the details are lost.
Use the Histogram
The histogram is a graphical representation of the tone distribution in the selected image. The ends of the graph are the brightest and darkest tones in the photo. Any portions of the histogram that touch either edge indicates a loss of detail, or what’s known as “clipping.”
Click the left arrow to enable the clipping warning to indicate areas in the shadows that have lost detail. The blue warning overlay dynamically updates as you make adjustments. In the histogram you can click and drag directly on tone regions to change them. Notice the corresponding slider values in the Basic panel also update.
Correcting underexposed photos can make colors in the midtone and areas appear a little less saturated than those in properly exposed photos. After making adjustments to correct underexposure, carefully inspect the colors. The saturation slider may need to be boosted to more closely match the coloring in the original shot.
For more detailed control over the color saturation, use the color saturation sliders for highlights, midtones, and shadows in the Color panel. You can also adjust the saturation of specific colors using the detailed adjustments on that panel.