OD (Optical Density) Measurement

Optical Density (OD) measurement quantifies how much light a substance absorbs or blocks as it passes through. It’s commonly used in laboratories to assess concentration of substances, like bacteria in a sample or DNA in a solution. A spectrophotometer shines light through the sample, and the OD value indicates how cloudy or opaque the sample is—the higher the OD, the more light is absorbed, signifying a greater concentration of the target substance. This method provides a quick, reliable way to monitor and compare sample amounts without disturbing the contents.