Transmittance
In the fields of optics and spectroscopy, transmittance is the fraction of incident light at a specified wavelength that passes through a sample. The transmittance T of a sample is defined as
- <math>T = I / I_0<math>,
where <math>I_0<math> is the intensity of the incident light and I is the intensity of the light coming out of the sample. Transmittance is related to absorbance A as
- <math>A = - \log_{10} T<math>
Note that the term transmission refers to the physical process of light passing through a sample, whereas transmittance refers to the mathematical quantity.
