Underexposure

Underexposure is a condition in which an image receives less light than required to render tones accurately. In photography and cinematography, it results in a darker-than-intended image with reduced detail in the shadows and, in some cases, color shifts. In digital imaging, underexposed areas often show increased noise and a compressed tonal range; in traditional film, underexposure reduces negative density and can limit shadow detail, requiring adjustments in printing or development.

Common causes include incorrect metering (especially in scenes with bright highlights and dark subjects), using negative exposure compensation, choosing fast shutter speeds, small apertures, or low ISO settings, and shooting against a strong light source or in low-light conditions. The result is a histogram that skews toward the left, with possible clipped shadows if the exposure is pushed too far.

Prevention and correction rely on adjusting the exposure triangle: aperture, shutter speed, and ISO. In digital work, photographers often use exposure compensation, shoot in RAW for post-processing flexibility, bracket exposures, or rely on histograms to achieve a balanced result. Lighting can be added or altered, and flash or reflectors can be used to brighten shadows without overexposing highlights. In post-processing, exposure and curves adjustments can recover some detail, though severely underexposed areas may be unrecoverable.

In other contexts, such as film stock, underexposure reduces image density and may require printing corrections; in radiography, underexposure yields nondiagnostic images and must be corrected within safety and diagnostic quality guidelines.