This is the light in a work of art. It is based on how we see light in the world. Illumination or lighting can have many different qualities such as the amount of light, the level that the light is coming from and the color of the light. For instance a foggy day produces one type of illumination that is soft, fuzzy and has light softly bouncing everywhere without strong and sharp value contrasts. The illumination of late afternoon or early evening when the sun is low produces long shadows and less direct light as the sun lowers. The illumination of mid day is very bright and sharp with shadows that are just small dark lines around the bases of figures and forms. Another thing to observe about illumination in addition to the qualities of the atmosphere (sunny or foggy, etc.) and the angle of the light source is how many light sources are there? With artificial lighting there can be multiple light sources. With reflected light there are also multiple secondary sources. Illumination or light can unify a drawing or painting, produce mood and drama, make great color changes and it can more fully realize the effect of the illusion of three-dimensional form. Setting up dramatically lighted still life will help you study illumination.