HDR

HDR (high dynamic range) is a term that indicates that the dynamic range of a colour exceeds the standard range between 0 and 1 (inclusive). This means that the colour can exceed the brightness of plain white (#FFFFFF). Whether or not the screen can display these colours is not relevant.

On a standard dynamic range image, the brightness of a white T shirt would equal that of the sun. On a display, this is fine, but to the game engine this introduces problematic ambiguity in certain contexts. Common examples include bloom and blurring of any kind (motion blur, depth of field, etc.).

Another notable advantage is when HDRIs (high dynamic range images) are used as environment maps. This provides an almost perfectly accurate snapshot of the lighting in a scene. The specular highlights of an object will naturally be more visible than the rest of the reflections.