Metrology for Temporal Light Modulation 20NRM01

Training session on the measurement of temporal light modulation (TLM)


On 18th of April 2024 the normative joint research project (JRP) “Metrology for Temporal Light Modulation” (EMPIR JRP 20NRM01 MetTLM) invites you to a one-day training course on the measurement of temporal light modulation (TLM). The training will encompass sessions on equipment, measurement methods as well as the verification methods estimation of measurement uncertainty and will be held as an in-person event at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, Germany.

Still photo of a Christmas tree (left) and photo obtained during a camera pan (right)
visualizing the phantom array effect of a set of LED fairy lights that include different TLM waveforms

Content of the training

The training will encompass:

  • Equipment specification, characterization and calibration,
  • Methods of measurements in laboratory settings and field measurements
  • Sources of measurement uncertainty originating from the measurement devices or modulated light sources under test.
  • Practical demonstrations of systematic measurement errors arising during the determination of TLM and TLA metrics, with advice on how to avoid common potential errors.
  • Introduction of validation and verification of methods for traceable TLM measurement,
  • Issues in results from imaging luminance measurement devices originating from temporal light modulation (TLM) with respect to different measurement principles, i.e. a global shutter or rolling shutter, will be considered.

The training will also include demonstrations of temporal light artefacts by vivid examples inside optical measurement laboratories of PTB, i.e. LED based screens for advertisement and fairy lights, and provide the possibility for a hands-on on TLM measurement devices from different manufactures available in the MetTLM consortium.

Targeted audience and prerequisites

The training session addresses technicians and engineers of testing laboratories, National Metrology Institutes and manufacturers of instruments and luminaires who are interested measurement and measurement uncertainty of TLM.
Participants are expected to already have substantial knowledge in the field of Temporal Light Modulation prior to the event, i.e. knowledge of metrics for TLM and TLA, as well as on principles regarding traceability and measurement uncertainty. In particular, it is requested that each participant already has the Technical Report CIE 249:2022 “Visual Aspects of Time-Modulated Lighting Systems” at hand.
Participants are expected to be familiar with the vocabulary of CIE Technical Note 012:2021, eco design regulation (Ecodesign Directive 2009/125/EC), and with the basics of ISO/IEC Guide 99:2007-12 (VIM) and JCGM 100:2008 “Guide to the expression of uncertainty in measurement (GUM)” including its Supplement 1 (JCGM 101:2008) and Supplement 2 (JCGM 102:2011).

Registration for the Training
Please register for the training session via E-mail to by 2024 April 10th. Subsequently a confirmation of registration and detailed information about the agenda including the training location and useful information on public transport will be provided.

Practical Information
The training session is provided free of charge as an in-person event for one full day in Braunschweig, Germany. Participants need to cover their own travel expenses.
A registration in advance to the training session is required. Due to the practical demonstrations the number of participants is restricted.
Date: 18. April 2024
Location: Physikalisch-Techische Bundesanstalt (PTB) Braunschweig, Bundessallee 100, 38116 Braunschweig, Germany
Registration: by 10th April 2024 via e-mail to
Contact: Johannes Ledig, phone:

About the project

LED-based lighting contributes to energy saving and the reduction of the environmental impact of lighting. However, LED lamps can show fluctuations in the light output known as temporal light modulation (TLM) which could, above certain limits and under certain conditions, impact the health, well-being and safety of people.
The overall aim of this project is to create the metrology infrastructure required for the measurement of TLM and to contribute to the development of standardisation on the measurement of TLM. For more information see


This project (20NRM01 MetTLM) has received funding from the EMPIR programme co-financed by the Participating States and from the European Union's Horizon 2020 research and innovation programme.

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