Category: Light

New Definition of Kelvin Goes Into Effect Today

Science geeks everywhere are celebrating World Metrology Day today.   Today has also been chosen by Bureau International des Poids et Mesures (International Bureau of Weights and Measures) to implement changes to the International System of Units or the SI.  The changes are to the definitions of the kilogram, ampere, kelvin, and mole.  

Misunderstanding CRI

Last Friday I took my class on a visit to a fixture manufacturer’s showroom.  The visit was pretty successful, but I had one issue with the information that was presented.  This manufacturer’s rep presented their CRI 80 and CRI 90 products by saying that CRI 80 dulls colors and CRI 90 makes colors “pop”.  I can’t blame him too much, after all it’s a common misconception that higher CRI is “better.”  However, it’s not true so let’s take a look.

Fixing CRI, But Not Really

A couple of weeks ago the Global Lighting Association (GLA)  published Application of CIE 13.3-1995 with Associated CRI-based Color Rendition Properties.  It proposes TM-30 like metrics to supplement CRI Ra.  Specifically, it proposes a color gamut index, Ga, that is similar to TM-30’s Rand a set of chroma indices, Ci, similar to TM-30’s Rch,hj.  At first glance I can see some specifiers getting excited about this.  Since it’s based on CRI it’s already somewhat familiar so it should be easier to learn.  But…

International Day of Light 2018

Today, May 16th, is the International Day of Light 2018.  It began in 2015 when the U.N. declared  The International Year of Light and Light-based Technologies.  Today, the International Day of Light is

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