At the heart of every measurement system is ascertaining that results are correct. Hence, light measurement systems – even handheld devices – need to be calibrated regularly. As equipment gradually changes in time (as a result of physical deterioration, temperature variation and contamination) regular maintenance is 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 that units are recalibrated 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 reference light sources, the CALI –T50/CALI-DT300 lamps, or you can choose to use a calibration lamp of your choice. The CALI-T50 accessory is included in LabSpion.

All CALI-T50/ CALI-DT300 light sources are traceable to Viso’s NIST (National Institute of Standards and Technology) calibration lamps.

Important: Calibrations must be made in a dark environment with non-reflective surfaces.


Let Viso Systems help you with your recalibrations. Just send your sensor (alternatively you LightSpion suitcase) to Copenhagen for recalibration. Expect 1-2 weeks lead time including UPS freight. Naturally, our goal is to keep your lab down-time as low as possible! Send your request directly to Viso headquarters or your local distributor –