The CIE is pleased to share the signing of a new Memorandum of Understanding (MoU) with the International Bureau of Weights and Measures (BIPM). Signed on 15 July 2025 in Varenna, Italy, this agreement marks the continuation and strengthening of our long-standing collaboration to advance global comparability and standardization in optical measurements, including photometry, radiometry, and digital metrology.
This new MoU, signed by Dr. Diana Wernisch, Secretary General of the CIE, and Dr. Martin Milton, Director of the BIPM, replaces the earlier agreement signed in 2007 between CIE and the International Committee for Weights and Measures (CIPM). It formalises and updates our cooperation with the BIPM directly, recognising the evolving needs of the international measurement community.
The BIPM and CIE have enjoyed an excellent and longstanding collaboration through their work with the Consultative Committee for Photometry and Radiometry (CCPR), established in 1933, and the Consultative Committee for Units (CCU), set up in 1964. In 2007, this cooperation was further formalised when CIE and CIPM signed their first agreement, marking nearly two decades of structured partnership in maintaining global consistency in optical measurement science.
Under the new agreement, cooperation will continue in several key areas:
- Ensuring that measurements of light, optical radiation, colour, optical properties of materials, and photobiological and photochemical quantities are traceable to the International System of Units (SI) and internationally recognized through the CIPM Mutual Recognition Arrangement (MRA).
- Maintaining the definition of photometric units based on the constant for the luminous efficacy of defined visible radiation, Kcd to remain fit for purpose across all relevant applications, with consideration for ongoing advances in physiological research.
- Collaborating on the development, implementation, and promotion of the SI Digital Framework, supporting the digital transformation in the international scientific and quality infrastructure.
At the event marking this agreement, CIE was represented by Past President Dr. Peter Blattner and Secretary General Dr. Diana Wernisch. CIE is proud of this long-standing partnership and looks forward to continued collaboration in strengthening global measurement standards. During the ceremony, CIE was gifted with the BIPM Medal, issued on the occasion of BIPM’s 150th anniversary. The CIE delegation was pleased to receive this medal, which recognises over a century of valuable cooperation between the two organisations.
The signed MoU is available here.