Diffuse Reflectance is reflected energy that has interacted with the sample. This technique requires a sample with a very uniform particle size. Like the KBr pellet method, the sample finely ground with KBr, but is not pressed into a pellet. This saves some time and eliminates the need for a press and dies. A rotating sample tray hold many sample cups, and spectra can be collected much faster than with the KBr pellet method. Reflected light that has not interacted with the sample (other than being reflected) is termed specular reflectance.{insert figures}