LRV Cal­cu­la­tor for ADA Signage

How To Mea­sure Col­or Contrast

As an indus­try ​‘rule of thumb’, a 70% Light Reflectance Val­ue (LRV) con­trast between sign text and back­ground col­ors is an ide­al guide­line to fol­low when eval­u­at­ing col­or and fin­ish options. LRV val­ues for all paint fin­ish­es in our Stan­dard Ranges and the cal­cu­la­tion used to cal­cu­late LRV con­trast have been pro­vid­ed for you in our Stan­dard Col­or Doc­u­men­ta­tion. Most major paint man­u­fac­tur­ers include LRV val­ues for their col­ors in their swatch books. These val­ues, along with ours, can be used in the man­u­al cal­cu­la­tion below.

LRV Reflectance Formula

Con­trast = ( B1 — B2 ) x 100 / B1

B1 = light reflectance val­ue (LRV) of lighter area

B2 = light reflectance val­ue (LRV) of dark­er area

Our expe­ri­ence has shown that the 70% fig­ure is not a mag­ic num­ber. Con­trasts of a few per­cent­age points below the rec­om­mend­ed fig­ure, depend­ing on the col­ors cho­sen, can often yield leg­i­ble results.

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