Accurate measurement of the wavelengths and amplitudes emitted by light sources is vital for a range of applications. These include monitoring essential climate variables, assessing the suitability of lighting in workplaces, and various industrial processes. SI traceability for measurements of these values has previously been achieved using standards based on incandescent lamps.

However, as incandescent lamps are phased out and solid-state-lighting alternatives (e.g., LEDs) become more prevalent, these standards also need to adapt.

This project will develop new transfer standards in the ultraviolet, visible, and near-infrared ranges to replace current incandescent lamp standards, with measurement uncertainties as low as 0.5 %. It will also develop detector-based methods for SI-traceability of spectral irradiance, defining minimum requirements for spectroradiometers to be used as transfer standards and developing procedures for their calibration. Good practice guidelines for these new standard sources and calibration procedures will also be developed and their applicability will be demonstrated through an intercomparison campaign involving calibration laboratories and at least 3 end-users.

The outcomes of the project will ensure that standards relating to measuring light are secure after the phaseout of incandescent lighting. Keeping these standards relevant to the most up-to-date lighting technology will improve confidence in the climate, workplace and industrial light monitoring practices which utilise them, and will have positive effects on their accuracy and traceability.