Dr. Soontorn Chanyawadee, from NIMT, participated in the Workshop on Photometer Calibration: Utilizing LED Lights in Accordance with CIE 251:2023 Standard hosted by the National Institute of Metrology (NIM) on 1–4 June 2026 in Beijing, China.
The workshop brought together experts in optical metrology and photometric measurements to address emerging challenges associated with the global transition from conventional lighting technologies to light-emitting diode (LED) lighting systems. As countries worldwide pursue energy efficiency, carbon neutrality, and net-zero emission goals, LED technology has become the dominant lighting solution. This transition has created new requirements for the calibration and measurement of photometric instruments.
During the workshop, participants gained in-depth knowledge of the newly introduced CIE Reference Spectrum L41, which has been recommended by the International Commission on Illumination (CIE) under CIE 251:2023 as a new reference standard for calibrating photometers and luminance meters. The adoption of LED-based reference standards is necessary because the spectral characteristics of LEDs differ significantly from those of traditional incandescent lamps used in conventional calibration systems, potentially leading to measurement errors caused by spectral mismatch.
Through lectures and hands-on laboratory sessions conducted by experts from NIM China, Dr. Soontorn received practical training in illuminance meter calibration using LED reference sources and explored advanced calibration techniques for modern photometric instruments. The workshop also provided valuable opportunities to exchange technical knowledge and experiences with metrology specialists and representatives from APEC member economies.
The knowledge and experience gained from this workshop will support NIMT’s efforts to enhance its photometric calibration capabilities and align national measurement services with the latest international standards. In particular, the workshop contributes to NIMT’s preparation for implementing CIE Reference Spectrum L41 and developing measurement methods that meet the requirements of CIE 251:2023.
Participation in this international workshop also strengthened NIMT’s collaborative network with leading metrology institutes and experts in the field of optical metrology, paving the way for future technical cooperation, research activities, and international measurement comparisons.
NIMT remains committed to maintaining and advancing national measurement standards to support technological innovation, industrial competitiveness, and sustainable development in the evolving global lighting industry.
