Phong
Phong reflection model is an historical technique that describes the way a surface reflects light. It generates diffuse reflections from rough surfaces and glossy reflections from shiny surfaces - based on the fact that shiny surfaces have small intense glossy highlights, while dull surfaces have large highlights that fall off more gradually.
Phong Material
Diffuse Color - Defines the base color by setting the shader diffuse reflection color. This is the color the shader takes on when the light reflection of the surface is spread in many directions. Use the slider to change the brightness. Click the color field on the right to open the color chooser. Assigning a texture to the diffuse color projects it onto the surface. The appearance is a combination of the defined color and the assigned texture.
Glossy Color - Sets the material’s color for surfaces glossy reflections. Use the slider to change the brightness. Click the color field on the right to open the color chooser. Assigning a texture to the glossy channel defines areas in which different gloss intensities appear with the help of a texture. The glossy color depends finally on both the defined color and the assigned texture file.
Roughness - Controls light reflections on top of the surface. The higher the value, the rougher the microscopic structure on top of the surface and more diffuse are the reflections.
Diffuse Backscattering - Defines the roughness of the material’s diffuse component. A value of 0.0 means smooth (Lambertian surface), a value of 1.0 means rough (for example, concrete).
For further information on the other attributes, see the following: