Pro Lite Technology

Photometry, Colorimetry & Spectroradiometry -
a Training Course on the Science of Light Measurement

Photometry Training

Course Overview

Lighting is an exciting and rapidly developing area - LEDs and solid state lighting promise not only energy efficiency but also design flexibility. Yet LED specifications are often mistrusted. Together with measurement service specialists Photometric Testing, Pro-Lite holds regular one day training courses in photometry and light measurement that help you to understand LED and lighting specifications, to seperate truth from fiction and show you how to measure and express the output of your products. An optional practical session is offered on the morning of the second day where delegates can gain hands-on experience with the latest, state-of-the-art measurement equipment.

Why is the subject of LED specifications so hotly disputed? LEDs are mass produced and there is a significant variation in the brightness and colour of the LEDs as they come off the production line. Manufacturers test and group LEDs by brightness and colour (a process called "binning"). However, in general, LEDs are tested under very idealised conditions - a short flash of current is passed and the LED does not have chance to achieve a steady state temperature. When LEDs are clustered into a luminaire or other product, the LED temperature rises above the nominal 25°C and the light output falls. At the 70-80°C operating temperature typical of many light fittings, the LED flux (lumen output) has dropped by 30% compared to the initial level (some people refer to this as "hot lumens" versus "cold lumens"). At the same time, the correlated colour temperature (CCT) of the LEDs rises and the colour rendering (CRI) also changes. Unlike traditional lamps, you have to test the assembled luminaire with LEDs fitted as a finished product - simply estimating luminaire performance based on the output of the component LEDs will be very misleading. Our course will explain both the theory and practice of how to measure the output of LEDs and luminaires.

The following comments about our training course were kindly provided by staff at retail lighting specialists Microlights Ltd. Thanks to Anna Enright (New Product Project Manager) and Philip Sharpe (Marketing Manager):

"Microlights pride ourselves on understanding customer needs. [Pro-Lite] understood our training requirements and educated us so that we can pass technical information on to our customers in a clear and concise way"

"Technical information, provided in a non-technical way"

"Detailed, tailored training - yet easy to understand"

"Training that was expert, smart and focussed to our needs"

Our training course has been developed over 10 years and has previously been presented to in excess of 750 delegates. Our trainers are noted for their ability to communicate complex subjects in a clear, easily understood way and we have consistently been awarded top marks for the quality of our teaching. Our course will empower all of these working with the next generation of ultra efficient lighting to understand the important optical metrics and communicate clearly and effectively within their own supply chain and with customers. The course will be of value to both technical and as well as marketing staff working with displays and lighting.

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Key Information

Dates:   Click here for course dates Location:   Photometric Testing, GL51 6PN
Day 1 (Theory) 09:00 - 17:00
Day 2 (Practical) 09:00 - 13:00
Robert Yeo
David Chambers
Theory only £450 + VAT
Practical only £450 + VAT
Combined £850 + VAT
To Register:  
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Course Syllabus

Day 1: Theory (09:00 - 17:00)             

§ 1.0 The Human Vision System

  • Understand how we perceive light - the photopic response of the eye and how our perception varies at low levels of light
  • Understand how we perceive colour - how human vision is based on the relative amounts of red, green and blue light that we see

§ 2.0 Measurement Metrics

  • Learn how to express the amount of light - the differences between total flux (lumens), the intensity shining in a particular direction (candelas), the intensity that illuminates a surface at a certain distance (illuminance in lux) and the brightness of light emitted by or reflected from a surface (luminance in candelas per square meter)
  • Learn how to express the colour of a light source - chromaticity (colour space) diagrams, chromaticity coordinates (xy, uv, u'v') and the "simplified" colour metrics of correlated colour temperature (CCT in Kelvin) and dominant wavelength

§ 3.0 Measurement Equipment

  • Learn about the types of equipment used as well as the practicalities of measuring the amount and colour of light:
    a. Integrating spheres for total flux measurements
    b. Photometers for measuring illuminance and luminous intensity
    c. Spot photometers for measuring the brightness of displays and signs
    d. Colorimeters for measuring colour and colour temperature of light sources
    e. Spectroradiometers - being a more accurate type of photometer or colorimeter, as well as
        recording colour rendering
    f. Goniophotometers for measuring the intensity or luminance of a light source or display as
       function of angle, and how to compute view angles and generate standard photometric
       files in .ies and .ldt formats
  • Issues with measuring LEDs – be aware of the potential pitfalls

§ 4.0 New Modules for 2017

  • Flicker - what it is, how is it caused, why it's a problem and how to measure it. We'll also explain the new IEEE 1789 flicker standard and how to determine if your light source    exhibits good flicker or bad flicker
  • Colour rendering - what it is, how it is measured and the differences between the new IES TM-30-15 colour rendering metric and the original CIE 13.3 system, and how it levels the playing field for LED lighting
  • Photobiological safety - now that photobiological safety assessment in accordance with BS EN 62471 is a requirement of the updated luminaire standard BS EN 60598, we'll revisit how to make photobiological safety measurements and to determine the appropriate risk group for your product

Day 2: Practical Projects (09:00 - 13:00)

§ 1.0 Measuring Luminous Flux, CCT & CRI

  • Calibrating and using an integrating sphere to measure the performance of a lamp

§ 2.0 Standard Photometric Data

  • Measuring the luminous intensity distribution from a luminaire and compiling / manipulating photometric data files in .ies and .ldt formats

§ 3.0 Studying the Inverse Squared Law

  • Measuring illuminance at different distances from a lamp and calculating luminous intensity; demonstrating the near-field versus far-field

§ 4.0 Luminance Measurements

  • Measuring luminance and comparing readings between a spot photometer, an imaging photometer and a spot spectroradiometer
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