Standard Reference Method or SRM is a system modern brewers use to measure color intensity, roughly darkness, of a beer or malted grain. This method involves the use of spectrophotometry to assign a number of degrees SRM to light intensity. The SRM number is defined as 10 times the absorbance of a sample at 430 nanometers measured through a .5-inch cell. The 430-nanometer wavelength corresponds to a deep blue light, and is the wavelength at which beers appear most different from each other. Degrees SRM are related to the current EBC standard by: ;