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  • What happens to the light output if all the lamps in a street are replaced by LED lighting? And how is this related to the electrical power consumed? To provide answers to these kinds of questions we use various techniques such as mapping out the the specific light output, the intensity distribution and the colour-related characteristics of the light emitted.

    Light is measured in numerous applications: from interior to maritime lighting and from obstruction to operating theatre lighting. And for biological and pharmaceutical research too, it is important to be able to determine the characteristics of light sources accurately. To establish climatic developments, too, measurements are done using optical instruments from the surface and from satellites.

    Optical measurements are used to determine temperature as well. This is called radiation thermometry. The use of thermometers often becomes impossible at temperatures above 1000°C, simply because most meters melt. At these relatively high temperatures however, radiation is also emitted that can be measured accurately with optical measurement instruments.

    VSL supplies different services in the field of light measurements across a wide spectrum: from infra-red through visible to UV light. In some applications, the human perception of the light is the main issue (photometry), while in others, the energy content by wavelength is wanted (radiometry).

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    Jair Blom
    Department Sales & Planning

    Direct contact

    Optical characteristics of sources and detectors but also the spectral characteristics of materials (the amount of colour from the colour spectrum that is reflected or absorbed) are measured by means of a detector or a light source. For an accurate and dependable measurement, these measurement resources must be calibrated regularly. VSL provides the lowest measurement uncertainty and makes measurements directly traceable to the primary standard.

    Detectors and sources
    In the calibration of detectors and sources, both the light output (lighting strength and light flux) and the electrical consumption can be measured. The spatial characteristics too, that is the spatial way in which the source emits, and colour characteristics such as colour temperature, colour coordinates and the colour rendering index can be mapped out accurately.

    The spectral irradiation of both photometric and radiometric sources can be determined. In this way, traceability is provided for devices including illumination and luminance meters and spectro- and filter radiometers.

    Optical filters
    Optical filters are used in the automotive and pharmaceuticals industries among others. VSL conducts application-specific calibrations of filters, the results of which are used for traceability of optical transmission and wavelength. The calibration results are expressed in spectrally-resolved transmission, colour shift, opacity or wavelength of maximum absorption.

  • VSL’s extensive knowledge and experience in the light measurements field is regularly requested for specialist applications including by government bodies, hospitals, research institutions and manufacturers of light sources and measurement systems. The measurement results from VSL as an independent party are internationally recognised and form a strong underpinning of the performance of your product to customers and other interested parties.

    With our thorough knowledge of measurements and interpretation of measurement data and our extensive test facilities, VSL can provide you with services including:

    • Characterisation of new light sources and detectors. Mapping out the spatial, spectral and time-dependent characteristics of newly-developed light sources and detectors and comparing these to specifications.
    • Development and validation of measurement solutions.
    • Determination of measurement uncertainty and tracking down measurement errors. Quantification of measurements through preparation of an uncertainty budget and advice about the reduction of measurement uncertainty.
    • Advice regarding measurement methods for laws and regulations. Laws and regulations are becoming ever more technical in nature. With our expertise, we can indicate how a measurement can be made testable and we provide support in the establishment of sensible requirements.
    • Independent judgement in claims or disputes. In the case of claims or disputes, an independent and dependable measurement can provide resolution.

    Of course, each situation is unique. Would you like to know what we can do for you? Please contact us.

  • To ensure optimum quality of their measurements, laboratories frequently hold in-house quality checks. However, over time deviations in the measurement equipment can occur that cannot be detected by these checks. VSL regularly organises (international) interlaboratory comparisons, through which your laboratory’s measurement results are compared anonymously to those from VSL as primary standards laboratory and those from other participating laboratories.

    In the area of Optics, VSL regularly organises proficiency tests (PTs) concerning LED-based measurements, among other things.

    Need another interlaboratory comparison? 
    Do you require another type of proficiency testing? Then please let us know!
    It is also possible to organise a bilateral comparison with VSL.

    Click here for more information about interlaboratory comparisons.

  • Various manufacturers of measurement instruments calibrate these in their own calibration facilities. They do this to check that the newly-produced instruments comply with the requirements, to check stability, or for periodic recalibration. Of course, the purchaser of the measurement instrument must have faith in the facility and so the measurement uncertainty is important.

    Test facility performance
    VSL offers CMC Certification. CMC stands for Calibration and Measurement Capabilities. In this, only the performance of the test facility is considered. You receive a certificate containing the calibration facility’s measurement uncertainty and a manual about traceability. With this certificate, you can demonstrate that the measurement uncertainty has been established by an authoritative and independent national metrology institute (NMI).

    Click here for more information.

  • Would you like to know more about the accurate measurement of light? VSL offers training courses which are presented by specialists in their field of work. Theory is always combined with practice.

    After the course you will receive a certificate of participation.