Light is the photographer's medium, and a electronic flash, or whatever source is used. It has an photograph is the image of a pattern of light recorded on effect on the materials it falls on, skin becomes tanned, film. The word photography means writing or drawing and fruit is ripened by the light of the sun. Depending with light. Without light there could be no vision or on the way in which light is received or rejected, a photography because it is light reflected from the world complex pattern of light, shade, and color results. around us that makes things visible to both our eyes and Other types of radiant energy, such as radio waves the eye of the camera. The nature of light has a critical and X rays, are similar to light but the eye cannot see effect on the pictures you make. Few photographers them. Thus they are not light. By definition, light is actually understand much about light. But they are not electromagnetic energy visible to the human eye. All alone. Scientists have never been able to agree fully other electromagnetic energy is invisible, therefore, is about the nature of light. However, certain useful things not considered light. Ultraviolet and infrared radiations are clear and well understood about how light behaves. are two such invisible radiations that are of concern to the photographer. 

Light is a form of electromagnetic radiant energy to which the eye is sensitive. It travels at tremendous speed Light makes up the visible spectrum, which is a small from its source, such as the sun, a fluorescent lamp, an part of the entire electromagnetic spectrum (fig. 1-1).

Figure 1-1. The electromagnetic energy spectrum.

Figure 1-2. Wavelength.