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Understanding Mesopic Photometry

Understanding Mesopic Photometry

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2013/10/08  If you are involved with outdoor area or roadway lighting design, you will undoubtedly encounter such terms as mesopic multipliers, scotopic lumens, and S/P ratios,...

Thoughts on Color Rendering

Thoughts on Color Rendering

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2014/01/05 UPDATE 14/10/06 - LightingEurope, the "Voice of the Lighting Industry," has just published their LightingEurope Position Paper on Color Quality. To summarize:...

The Kruithof Curve

The Kruithof Curve

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.  Published: 2015/01/12 UPDATE 16/04/09 - This metastudy: Fotois, S. 2106. "A Revised Kruithof Graph Based on Empirical Data," Leukos. (Published online 08 April 2016, DOI...

Sports Lighting Regulations

Sports Lighting Regulations

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2016/04/30  This blog article has a somewhat frustrating history. About a year ago, I was asked to volunteer my time to write a primer of light and color as it...

Mobile Light Pollution

Mobile Light Pollution

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2016/01/21 At first glance, this appears to be an innocuous question: How much light pollution is attributable to automotive headlights? It is also a good question in that if...

Mesopic Photometry and Statistics

Mesopic Photometry and Statistics

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2014/04/21 One of the joys of statistics is that you can never be proven wrong ... In a previous All Things Lighting article titled "Understanding Mesopic Photometry" (October...

Light Pollution and Uplight Ratings

Light Pollution and Uplight Ratings

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2015/07/20 "Oh, East is East, and West is West, and never the twain shall meet." When Rudyard Kipling wrote this line in his poem The Ballad of East and West (Kipling 1892),...

LICASO and DAYSIM

LICASO and DAYSIM

 Ian Ashdown1, Chris Jackson2, Joel Spahn3, Todd Saemisch3  1. SunTracker Technologies Ltd., Victoria, Canada. 2. Lighting Analysts Ltd., London, UK. 3. Lighting Analysts Inc., Littleton, CO. Published: 2017/02/11 LICASO and DAYSIM are daylighting analysis...