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Kruithof Revisited

Kruithof Revisited

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2015/11/24 A previous blog article -- The Kruithof Curve -- examined the history of the Kruithof curve (Kruithof 1941]) shown in FIG. 1: FIG. 1 – Kruithof curve, modern version...

Giving Light

Giving Light

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2014/05/12 Giving light ... this phrase symbolizes a new philosophy of lighting design, a philosophy in the sense of how we think about the lighting design process. Much like the...

Filtered LEDs and Light Pollution

Filtered LEDs and Light Pollution

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2016/03/03 UPDATE 2016/03/03 - Revised Figure 6. The problem is astronomical -- the blue light emitted by LED roadway luminaires has been shown to contribute to light...

Daylight Factors

Daylight Factors

Ian Ashdown, P. Eng., FIES,Senior Scientist, SunTracker Technologies Ltd. Published: 2014/03/05  Nine out of ten daylight simulation programs agree ... and therein lies a story worth retelling. Daylight in History The story begins in the sixth century with the...

Color Temperature and Outdoor Lighting

Color Temperature and Outdoor Lighting

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2015/07/22 UPDATE: Sports field lighting analysis added 15/10/12. [An edited version of this article was published as "STREET LIGHTS: Light pollution depends on the light source CCT"...

Climate-Based Daylight Modeling

Climate-Based Daylight Modeling

 Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published:  2016/03/26 daylight, n. The light of day. Apart from having a wonderfully circular definition in most English-language dictionaries, daylight really is just another form...

Blue Light Hazards and                                      Television

Blue Light Hazards and Television

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.  Published: 2017/05/19  If you have grandchildren, you may be old enough to remember “black and white” (that is, monochrome) televisions sets with rabbit ear antennae and some of the...

Blue Light Hazard… Or Not?

Blue Light Hazard… Or Not?

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2014/11/05 As a professional lighting designer, you will likely have read about the “blue light hazard” associated with white light-emitting diodes. You will have seen...