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.