It wasn’t that long ago that an underexposed frame of film was a total loss. An underexposed color or black and white negative could be printed but the results were grainy, lacked contrast and barely salvageable. An underexposed transparency was hopeless since no detail could be extracted from underexposed black film.
That has all changed in the digital age. It does not mean that underexposure is no longer relevant. But today it is possible to salvage the most grossly underexposed photos and turn them into something that is generally acceptable.
Photoshop and Lightroom to the Rescue
The primary tools for salvaging underexposure are Adobe Photoshop and Lightroom. There are multiple methods for using both to rescue underexposed shots. One is to duplicate multiple layers in Photoshop and blend them in screen mode. The example at right shows before and after results of this process.
Lightroom offers more complex methods of salvaging underexposures as is detailed in this tutorial. One bit of generally accepted advice is to shoot RAW. This makes it easier to extract more detail from underexposed areas. But even JPEGs can be salvaged with Photoshop techniques as this tutorial shows.
As the many tutorials available on line demonstrate, underexposed photos can be saved in a number of ways. But as with most things there is a tradeoff. Extracting detail from darkness increases grain. Grain can be reduced digitally but at the loss of sharpness. And all of this correction and manipulation of an unacceptably dark photo can take a fair amount of processing time.
The point is there is no complete substitute for proper exposure. Underexposure that would be a disaster on film can be rescued with digital techniques. But it is always best to get as close as possible to optimal exposure to begin with. In low light situations, camera stabilization with a tripod or alternative support like HandlePod is essential to give the camera sensor enough light. Don’t underexpose by hand holding with a fast shutter speed and plan to to fix it in post.