Light Lines July/August

Page 14

CIE-UK report

July/August 2021

COME TO TERMS John O’Hagan, chair of CIE-UK, reports on the global lighting body's recent activities including the latest edition of the International Lighting Vocabulary significant recent publication from the CIE has been the latest edition of the International Lighting Vocabulary (ILV). In developing technical publications, terminology is where it all begins. It provides a set of agreed definitions and terms for concepts common to a field, 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. In the CIE, terminology has always been a key subject. A century ago, in 1921, attendees at the Fifth Session of the CIE began to discuss the publication of a lighting vocabulary. The first edition of the ILV was published in 1938. Further editions followed and the 1987 edition was adopted by the International Electrotechnical Commission (IEC) for integration into their International Electrotechnical Vocabulary (IEV). In 2011 CIE published a new, completely revised edition, the first time as an International Standard, CIE S 017 ILV: International Lighting Vocabulary. The second edition was published in late 2020 with many new terms, reflecting advances in LED lighting and imaging technologies. The goal is to promote international standardisation 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 region, photobiology and photochemistry, and image technology. The terms and definitions from CIE



S 017:2020 have also been made available online through the e-ILV. There have also been two other new publications: Photometry of curved and flexible OLED and LED sources (CIE 242: 2000). The trend for high-tech products is towards the capability of flexibility: flexible lighting, displays, memory, solar cells and so on. Flexible products can be light, thin, break-resistant, and offer more creative freedom for the designer and lighting designer. It is not only for fun and fashion, but also because flexible products are practical – rollable displays can reduce the limitations of space and add further convenience for portable digital electronic products. As it is thin and light, flexible lighting can be integrated with clothes to increase safety at night. As flexible products become more common, measurement research is needed to support the industry. The report describes the methods of measuring photometric and colorimetric quantities for curved sources and gives guidance for the determination of measurement uncertainties. The measurement quantities include luminance, luminous flux, colour, reflectance and viewing angle. Discomfort glare in road lighting and vehicle lighting (CIE 243: 2021). This report provides an overview of the research methods, mathematical models and variables that are considered to influence discomfort glare, and describes the difficulties associated with its evaluation and measurement, and the variance in the models. The report aims to encourage

further research using methods recommended by the proposals it raises. Such research will generate a greater body of credible data, enabling the development of a more robust model. It is intended to update this report in due course with these additional data and a revised discomfort glare model. CIE-UK is the UK national committee of the International Commission on Illumination or CIE (Commission Internationale de l´Éclairage). SLL is a Sponsoring Organisation member. If you are interested in joining, or want more details, contact Allan Howard at

• The complete ILV can be purchased through the CIE Webshop. For more details on the e-ILV, go to: • UK members of SLL are eligible for the CIE-UK members’ discount for CIE publications, a two-thirds reduction on the list price. A discount is also available for some CIE events (including the CIE conference below). Please email for the discount code. Publications can be purchased via the relevant link on the CIE website: • CIE is making one publication available free of charge to its national committees for a year (until February 2022), including to SLL UK members (email sll@cibse. org). The document is Lighting for older people and people with visual impairment in buildings (CIE 227:2017). It summarises recommendations on lighting and the visual environment in interior spaces for healthy older people (defined as aged 50-plus) with normal vision, and people with low vision, and implements guidelines from CIE 196:2011 (CIE guide to increasing accessibility in light and lighting) into practical solutions. It provides (1) illuminance recommendations (2) state of art studies on how light helps people with low vision see objects and (3) guidelines for lighting practitioners on designing appropriate visual environments for people with low vision. • The 2021 CIE Mid-Term three-day conference will be held online from 27-29 September 2021. The theme is Light for Life – Living with Light. More details can be found at the conference website: