General lighting is undergoing a revolutionary change towards LED-based technologies. To provide firm scientific basis for the related colorimetric and photometric measurements, this paper presents the development of new white-LED-based illuminants for colorimetry, and their evaluation to recommend a new reference spectrum for calibration of photometers. Spectra of 1516 LED products were measured and used to calculate eight representative spectral power distributions for LED sources of different correlated colour temperature categories. The suitability of the calculated representative spectra for photometer calibration was studied by comparing average spectral mismatch errors with CIE Standard Illuminant A, which has been used for decades as the reference spectrum for incandescent standard lamps in calibration of photometers. It was found that in general, when compared with Standard Illuminant A, all the potential LED calibration spectra reduced spectral mismatch errors when measuring LED products. Out of the potential LED calibration spectra tested, the white LED spectrum with correlated colour temperature of 4103 K was found to be the most suitable candidate to complement Standard Illuminant A in luminous responsivity calibrations of photometers. When compared with Standard Illuminant A, employing the 4103 K reference spectrum reduced the spectral mismatch errors, on average, by approximately a factor of two in measurements of LED products and lighting. Furthermore, the new LED reference spectrum was found to reduce the spectral mismatch errors in measurements of daylight, and many types of fluorescent and discharge lamps, indicating that the proposed reference spectrum is a viable alternative to Standard Illuminant A for calibration of photometers.

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The impact of thermal radiation and its associated radiance temperature on nearly all facets of technology and society is tremendous. Reliable temperature measurements are in that context of vital importance in many areas in science, technology, industry and environmental protection. This implies the use of a sound traceability framework, involving accurate reference standards to begin with and a calibration procedure for radiation thermometers that incorporates all sources of measurement errors (uncertainties). Latter procedure should be two-fold; first a traceable comparison is made against a blackbody radiator, then the instrument is evaluated and/or calibrated in its application.In this paper all three traceability steps will be addressed, that is, the dissemination of the international temperature scale of 1990 (ITS-90) and the initial and on-site calibration of radiation thermometers. First two steps were investigated in detail and improved on European level in the TRIRAT program that was funded by the European Community. This included international intercomparisons for radiation thermometer calibrations and recommendations for the standardization and testing of infrared radiation thermometers as transfer standards. An other project, ILART, bridges the gap in traceability between initial calibrated radiation thermometers and their industrial application. It involves realization of a portable calibration facility, intrinsically insensitive for surface emissivity and reflection error using active two-color thermometry.

In this paper, the fisheye camera method is validated for spatial non-uniformity corrections in luminous flux measurements with integrating spheres. The method was tested in eight integrating spheres with six LED lamps, and the determined angular intensity distributions and spatial non-uniformity correction factors were compared with the results of five goniophotometers. The average closeness score, describing the similarity between any two distributions, was 94.6 out of 100 for the distributions obtained using the fisheye camera method when compared with the goniophotometric results. The average closeness score for the five goniophotometers, when each goniophotometer was compared with the other four, was . On average, the relative deviation between the two methods was 0.05% when calculating the spatial corrections. The most significant sources of uncertainty for the fisheye camera method were large, view-obstructing sphere elements residing close to the camera port.

New regulations are coming into force in several regions with respect to temporal light modulation (TLM) of lighting products. However, standardized test methods and even basic understanding of requirements are largely lacking in the area. Newly introduced metrics, like the stroboscopic visibility measure, are used in these regulations without the existence of standardized measurement methods to support these.-\n--\n-This document provides recommendations on measurement protocols to measure periodic waveforms and light modulations. The recommendations should enable test and calibration laboratories to apply the same measurement methodology and to report the results in a consistent and reproducible way. The document covers methods of measurement for TLM and temporal light artefacts (TLA) of lighting equipment. Its primary application is for general lighting purposes; however, the principles can be applied to other fields (e.g. display equipment, or facade lighting), though these generally require different input optics for the measurement equipment.-\n--\n-The recommendations given in this document can be used to measure non-periodic signals, but there might be specific aspects of these signals that will not be covered in this document (e.g. signal-triggering). This document sets the stage for an understanding of these new metrics and provides guidelines for the correct measurement of them. The document is meant to provide respective recommendations, which do not imply any kind of standardization. In addition to this Technical Note a CIE Technical Report is in preparation, which will cover a test method for flicker and the stroboscopic effect using existing or new metrics to be developed is going to follow this publication in due course. Keywords: temporal light artefacts, TLA, time-modulated lighting systems, temporal light modulation, TLM, LED, flicker, flicker index, modulation depth, percent flicker, Stroboscopic visibility measure, SVM