Algorithms used for Microspectroscopy

  Light is transmitted through the sample, collected by the objective and focused onto the aperture and simulaneously an image and spectrum are collected. Transmission spectrum from a microspectrophotometer.

Transmittance
Transmittance calculates a transmission spectrum from a sample and reference single-beam spectra.

From Two Single-Beam Spectra Transmission can produce a transmission spectrum from two single-beam spectra using the following formula:

Percent transmission calculation

where R is the single beam spectrum of the reference material, S is the single beam spectrum of the sample and D is the dark counts of the system.

From Absorbance Data:
A transmission spectrum can be generated from an absorbance spectrum using the following formula:

Convert absorbance to percent transmission.

where A is the absorbance value. This is a calculation from data that has already been collected.

Absorbance
Absorbance calculates an absorbance spectrum from a sample and reference single-beam spectra or from a transmission spectrum.

From Two Single-Beam Spectra:
Absorbance can produce an absorbance spectrum from two single-beam spectra using the following formula:

Absorbance calculation

where R is the single beam spectrum of the reference material, S is the single beam spectrum of the sample and D is the dark counts of the system.

From Transmission Data:
Absorbance can also generate an absorbance spectrum from a transmission spectrum using the following formula:

Convert percent transmission to absorance.

where %T is the percent transmittance value. This is a calculation from data that has already been collected.

Reflectance
Reflectance calculates a reflectance spectrum from a sample and reference single-beam spectra or from an log 1/R spectrum.

From Two Single-Beam Spectra:
Reflectance can produce a reflectance spectrum from two single-beam spectra using the following formula:

Percent reflectance calculation.

where R is the single beam spectrum of the reference material, S is the single beam spectrum of the sample and D is the dark counts of the system.