At the heart of every measurement system is ascertaining that results are correct. For light measurement systems – even handheld devices – this means regular calibration. As equipment gradually change in time (as a result of physical deterioration, temperature variation and contamination) regular calibrations are essential for realistic uncertainty estimates.

American NIST (National Institute of Standards and Technology) has issued an excellent paper on calibration issues and definitions: 


Viso Systems generally recommends recalibration every year or as a minimum every other year.

All Viso systems are delivered pre-calibrated but it is possible to make a custom calibration of the goniospectrometer if desired.

All Viso solutions have two memory areas where calibration data can be stored. The first memory area contains the factory calibration and cannot be edited. But the second area contains a custom calibration and can be changed by the user as many times as desired.

DO YOUR own calibrations

Viso Systems goniometers can be calibrated using Viso Systems own calibration light source, the CALI –T50/CALI-DT300 irradiance calibration lamps, or you can choose to use a calibration lamp of your choice.

All CALI-T50/CALI-DT300 light sources are traceable to Viso’s calibration lamps. Important: Calibrations must be made in a dark environment with non-reflective surfaces.


Let Viso Systems help you with your calibrations. Just send your sensor (alternatively you LightSpion suitcase) to Copenhagen for recalibration. Expect 1-2 weeks lead time incl. UPS freight. Send your request directly to Viso headquarters or your local distributor –