ABSTRACT
Photometry is the measurement of the propagation of light through various materials. The color of light is a function of its wavelength and a change in the color of light can be detected in the visible region with a change in wavelength. In photometry, measurement of the color intensity of a solution is governed by two laws, namely Beer’s law and Lambert’s law. Colorimetry is the measurement of color. It measures the concentration of substances that are colored or can be converted into colored compounds by a suitable reaction. This technique is very sensitive and requires minute amount of samples. A colorimeter is an instrument used to measure the concentration of colored substances. The spectrophotometer is based on the principle of Beer–Lambert law and is used to measure the amount of light absorbed by the sample. Spectrophotometers are of two types: single beam and double beam.
