Varjoarvo

Varjoarvo is a term used in Finnish imaging and computer graphics to describe the brightness level of shadowed parts of a scene or image. It refers to how dark the shadows appear and is a key factor in exposure, tone mapping, and shading calculations. In Finnish technical literature varjoarvo is treated as a quantitative descriptor for the luminance of shadow regions, distinct from highlight values.

The value of varjoarvo is typically expressed on a scale from 0 to 1 in normalized form, or as discrete gray levels such as 0–255 in common image formats, depending on the color pipeline or file format. In photography and video, varjoarvo is influenced by exposure settings, sensor response, gamma correction, and color management; during post-processing it is commonly adjusted with shadows controls to recover detail in dark areas or to shape contrast.

In computer graphics, shadow values are used in shading calculations, including techniques like shadow mapping and ambient occlusion. The varjoarvo in these contexts modulates how much direct or indirect light reaches a surface, affecting the final color and perceived depth of the image or scene. The concept is closely tied to dynamic range and tonal reproduction, as broader dynamic ranges allow more nuanced variation of varjoarvo between shadow and lit regions.

See also: dynamic range, exposure, tonal mapping, shadow mapping, brightness, grayscale.