Lambert's cosine law

Lambert's cosine law describes how the brightness of a surface viewed from different angles relates to the angle itself. Specifically, it states that the apparent brightness decreases proportionally to the cosine of the angle between the surface's normal (perpendicular) and the line of sight. When you look directly at a surface, it appears brightest; as you observe it at a steep angle, it seems dimmer. This principle explains how light reflects off matte, non-glossy surfaces and is fundamental in fields like optics, photography, and computer graphics for accurately modeling how surfaces appear under different lighting conditions.