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May 2018

The light plight

LRV test methods and their accuracies

A rule of thumb for surface LRVs is darker colors = low LRV (less light reflected) and lighter colors = high LRV (more light reflected), but manufacturers aren’t just sticking their noses into a bucket of paint or a floor tile and saying, “Yep, looks like a 42.”

When looking for the right Light Reflectance Value (LRV) for a space, be it a designer planning a hospital waiting room or a homeowner trying to find the right shade for their kitchen wall, the key is in the contrast. The Facilities Guidelines Institute recommends a 30-point difference in LRV between floors and walls, especially for healthcare environments, so accurate measurements are a necessity. Thankfully, manufacturers have started finding and publishing their products’ LRVs, making contrast easy. 

But how did they determine the LRV of that particular shade of blue? 

The two most common methods of determining a material’s LRV are using a spectrophotometer with the BS 8493:2008+A1:2010 – “Light Reflectance Value of a surface” test, or a hand-held colorimeter. 

More accurate than the rest, BS 8493:2008+A1:2010 with a spectrophotometer uses the CIE color system Y, x, and y values to determine LRV. Altro uses this test for all of our colors.

While hand-held colorimeters are useful for onsite approximation, they sometimes cannot measure metallic, glossy or curved surfaces, and lighting can skew results. The BS 8493+A1:2010 test measures new material while ignoring outside issues such as fading or lighting, and can be performed on a wider range of surfaces. 

If the BS 8493+A1:2010 or colorimeter tests aren’t available, a visual comparison between similarly-colored materials with known LRVs versus the sample to be tested can be done as a last resort. 

For more information on the test methods above, please see satra’s website on LRV testing.
Posted: 5/3/2018 4:03:59 PM by Jesse Wade | with 0 comments