A common language for interdisciplinary work in lighting science and application

ISC Member the International Commission on Illumination (CIE) recently released a new edition of the International Lighting Vocabulary (ILV), providing a common language for talking about the science and art of light and lighting. In this brief article, members of the CIE explain the background to the ILV.

This article was written by Peter Zwick, CIE Technical Manager and Chair of CIE Joint Technical Committee, JTC 8,  which prepared the 2nd edition of the ILV. Other contributors to the article were John O’Hagan, CIE Vice-President Standards (Public Health England), Jennifer Veitch, CIE Vice-President Technical (NRC Canada), and Kathryn Nield, General Secretary, CIE.

In the world of development of technical publications, terminology is where it all begins. It provides a set of agreed definitions and terms for concepts in specific fields, reducing the level of ambiguity associated with words and sentences. Before starting work on technical documents, experts first must agree on the terminology, so that everyone understands the concepts which are referred to. This is particularly important when disciplines come together to discuss topics that overlap their fields. Light and lighting, both science and application, brings together psychology, physiology, photobiology, photochemistry, vision science, engineering, physics, horticulture, and architecture.

In the International Commission on Illumination (CIE), terminology has always been a key subject. A century ago, in 1921, attendees at the 5th Session of the CIE began to discuss the publication of a lighting vocabulary. The first edition of the International Lighting Vocabulary (ILV) was published in 1938. Further editions followed in 1957, 1970 and 1987. The 1987 edition was adopted by the International Electrotechnical Commission (IEC) for integration into their International Electrotechnical Vocabulary (IEV).  

In 2011 the CIE published a new, completely revised edition of the ILV, the first time as an International Standard, CIE S 017 ILV: International Lighting Vocabulary. The second edition of this standard was published in late 2020 with many new terms, reflecting advances in technology for light-emitting diode (LED) lighting and imaging technologies – the latter of which has its own new section.

The aim of the ILV is to promote international standardization in the use of quantities, units, symbols and terminology related to the science and art of light and lighting, colour and vision, metrology of optical radiation over the ultraviolet, visible and infrared spectral regions, photobiology and photochemistry, and image technology. This vocabulary provides the definitions and essential information necessary for the understanding and correct usage of the terms included. It does not give extensive detail or explanations of the application of these terms; such information, relevant for experts in each specialized field, is available in the Technical Reports and International Standards published by the CIE.

To support the CIE’s aim to promote clear communication, good science, and international standardization in the use of quantities, units, symbols and terminology, the terms and definitions from CIE S 017:2020 have been made accessible online in an electronic version of the ILV, the e-ILV (http://cie.co.at/e-ilv), thus giving everyone free access to the definitions of CIE’s terminology standard.

For those who require the complete ILV, it can be purchased through the CIE Webshop.

Photo by Mimosa from Flicrk