text: Water is relatively transparent to visible light, near ultraviolet light, and far-red light, but it absorbs most ultraviolet light, infrared light, and microwaves. Most photoreceptors and photosynthetic pigments utilize the portion of the light spectrum that is transmitted well through water. Microwave ovens take advantage of waters opacity to microwave radiation to heat the water inside of foods. Waters light blue color is caused by weak absorption in the red part of the visible spectrum.