These bands are broad due to the unordered arrangement of the water molecules in the soil. Rotational processes involve molecules and occur with microwaves. In theory, the reflectance spectrum can be computed from knowledge of molecular and atomic structure and quantum mechanics, but soils are such complex mixtures of materials that this has been impossible thus far. The macroscopic interactions further complicate this. Water and OH- have absorption bands at 1.4 m.
Most colors are due to preferential absorptions.
The principal color is derived from the light that has penetrated and which, after being reduced by absorbing effect of the medium, is reflected by the second and third surface. Most colors are due to preferential absorption. The reflection from most surfaces is practically colorless. The principal color is derived from the light that has penetrated and which, after being reduced by the absorbing effect of the medium, is reflected by the second and third surface. The major factors influencing brightness are roughness, moisture, and organic matter.