Photo Research spotmeters are the standard of the industry...Select the model best suited to your needs.


Over five decades ago, Photo Research invented "spot" photometry when it introduced the Spectra Screen Brightness Meter for the motion picture industry. A few years later, a military customer inquired about measuring small spots on aircraft instrument panels and Photo Research produced the first Spectra Spotmeter microphotometer.

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The PR-1500 Spotmeter is a sensitive, versatile photomultiplier-tube photometer that can measure luminance(photometric brightness) at any distance from 1¾ inches (44 mm) to infinity without the need for accessory lenses or changes in calibration. The PR-1600 SpectraSpot, a silicon-cell photometer/radio meter, is designed for applications requiring the inherent stability and near infrared response of the silicon cell, without requiring the higher sensitivity of photo multiplier tubes.

Typical Applications
  • Display measurements
  • Cathode ray tube luminance
  • MIL-SPEC Lighting compliance
  • Street and Roadway lighting
  • Aircraft Panel Checkout
  • Material Reflectance Studies
  • Automotive Lighting
  • Color Temperature Determination
  • Airport lighting
  • Air pollution monitoring
  • Lamp quantity control
Photomultiplier Tubes

The standard photomultiplier phototube supplied has an S-20 response. These are specially selected and seasoned low-noise photodetectors.

Filter Turret

A 6-position filter turret is located between the aperture mirror and the photomultiplier detector. This turret contains the "photopic" filter which modifies the spectral response of the instrument to precisely match CIE or "human eye" response. This photopic filter is individual trimmed and calibrated for each SpotMeter. With this filter in position the Spot meter functions as a precision luminance photometer(photometric brightness meter).

Red and blue filters are included in standard instruments for relative tristimulus and color temperature measurements. (If special filters, such as red LED or scotopic response filters are installed, tristimulus and/or color temperature measurements capability is not available). Option 32 provides three individually trimmed colorimetric filters for red, blue and photopic making the PR-1500 a more accurate relative colorimeter. The filter turret has an OPEN position for use in making relative radiometric measurements. An internal calibration-reference source is mounted in the CAL position of the turret for quickly checking the instrument calibration prior to making a measurement.

USB Connectivity Option

We've made it easier to get data from the PR-1500 into the computer environment.

We now offer an optional Universal Serial Bus (USB) connectivity. This feature can be ordered with a new instrument, or retrofitted to existing instruments (must be returned to factory for retrofitting).

The USB enables all the capabilities of the BCD and more. The customer has a choice of ordering USB, BCD or both. Information returned from the USB bus is the DPM reading, exponent and sign, and CIE filter turret position.

We're also including a software installation CD, and fully documented sample software source code in C++, Visual Basic and LabView to make it easy for user integration.