The Pritchard Line of Photometers

The photometer has a long and respected history—it has been in use since 1861. Prior to its invention, the measurement of light was performed by comparing the luminous flux of a source with a standard source. The result, of course, was only as accurate as the human eye could make it. Today there are many ways for the photometer to detect and analyze light and many applications for which the information is used.

 

Detecting and Measuring the Light

 

A photometer usually detects light either by using photoresistors, high-resistance semiconductors; photodiodes that convert light into currents or photo multipliers that multiply the current generated by incident light. Once light has passed through a filter or monochromator, an optical device that transmits wavelengths of light, the photometer is able to perform an analysis of the spectral distribution of the light.

 

Reflectance Photometry

 

The reflectance of a surface in terms of wavelength is measured by a reflectance photometer. The target surface is bathed in white light and the reflected light is measured by means of a monochromator. A measurement of this kind is used for practical purposes, such as characterizing surface colors used in the paint industry.

 

Transmission of UV and Visible Light

 

Using light absorption measurements, optical instruments can be used to calculate a colored substance within a particular solution. Because of its reliability in this kind of research, the photometer is often used in biochemistry and analytical chemistry applications.

 

The Atomic Absorption Photometer

 

The job of an atomic absorption photometer is to measure the light produced by a hot flame. A specific solution is injected into the flame and once inside, any metals in the solution will take atomic form. Monochromatic light in the photometer is generated by the light from a discharge lamp with wavelengths that match the spectral lines of the metal. Light is ultimately absorbed by the metal in the flame with the absorption used to identify the concentration of metal in the original solution.

 

The Pritchard Line of Photometers

 

Several examples of today’s high-tech light-detection equipment can be found in the Pritchard line, representing the most widely used photometers in the world. Some models feature diode detectors, full-color touch screen displays and a USB interface. Many are portable, battery powered, with touch screen displays that offer full set-up and measurement features. The PR-810 model, for example, has a digital resolution of 16 bits and standard apertures of from 3 degrees to 0.125 degrees and a luminance range of from 0.0001 to 518,400 fL. The battery is a rechargeable lithium ion, which supplies more than 12 hours of continuous operation. The system also includes a 6-foot A/C adapter, DC with drivers and instruction manual and NIST traceable calibration, certified for six months.

 

An Experienced Provider Has the Solution

 

A portable, battery-powered photometer can be used in the field, in the lab or in a medical or industrial environment. It is an essential piece of equipment for automotive and aerospace testing purposes. In fact, you’ll find it in every kind of workplace from the dentist’s office to the local vegetable farm. When you have the need to detect and analyze light, an experienced provider can help you select the perfect kind of photometer for the job you have in mind.