Contrast, in physics and digital imaging, is a quantifiable property used to describe the difference in appearance between elements within a visual field. It is closely linked with the perceived brightness of objects and is typically defined by specific formulas that involve the luminances of the stimuli. For example, contrast can be quantified as ΔL/L near the luminance threshold, known as Weber contrast,[1] or as LH/LL at much higher luminances.[2] Further, contrast can result from differences in chromaticity, which are specified by colorimetric characteristics such as the color difference ΔE in the CIE 1976 UCS (Uniform Colour Space).
Understanding contrast is crucial in fields such as imaging and display technologies, where it significantly affects the quality of visual content rendering. The contrast of electronic visual displays is influenced by the type of signal driving mechanism used, which can be either analog or digital. This mechanism directly influences how well the display renders images under varying conditions. Additionally, the contrast is affected by ambient illumination and the viewer's direction of observation, which can alter perceived brightness and color accuracy.