As a courtesy to our customers,
Rowmark provides our findings for Light Reflectance Value of our Rowmark
ADA compliant materials.
Measurement of Rowmark Materials
Light Reflectance Value, or
LRV, is a measurement of the percentage of light that is reflected (and
conversely how much is absorbed) from a color (surface) when illuminated
by a light source. LRV runs
on a scale from 0% to 100%. Zero is assumed to be absolute black and 100%
being perfectly white. An
absolute black or perfectly reflecting white do not exist in our everyday
terms. The average blackest black has a LRV of approximately 5% and the
whitest white is approximately 85%.
Contrast is a calculation of the difference between the LRV between the
foreground color and the background color.
The current recommendation for detectable
warning surfaces is a contrast ratio of at least 70%.
Contrast Ratio is determined by the formula:
Contrast = [(B1-B2)/B1] x 100.
= LRV of the lighter color
B2 = LRV of the darker color
The LRV Test
LRV is measured with color measurement equipment,
specifically a spectrophotometer.
The value of the LRV is a measured result for each color.
The spectrophotometer will measure a “Y”
value which is equal to one
of the three CIE tristimulus values and essentially measures the luminous
reflectance (LRV) or transmittance (absorption) of a color.
The “Y” value is used in the above
calculation to determine the Contrast Ration between two colors.
Y = B in the calculation.
This test does not produce pass or fail results.
The scale of results varies from 0 (black) to 100 (white); however
most materials will fall well within these extremes.
Most guidelines suggest that a Contrast Ratio of 70% is
This test is not suitable for
some surfaces; therefore care must be taken when applying the test and its
results. For example, some surface finishes are effectively mirrors, which
have no lightness of their own but merely reflect the environment in which
they are placed.