Sets the value of DiffuseReflectionColour attribute. DiffuseReflectionColour is the degree of diffusion of the reflected light. In the case of specular surfaces there is no diffusion. The greater the diffusing power of the reflecting surface, the smaller the specular component of the reflected light, up to the point where only diffuse light is produced. A value of 1 means totally diffuse for that colour part of the light.

The factor can be measured physically and has three ratios for the red, green and blue part of the light.