ADA Color Contrast Charts
The complete ADA Standards for
Accessible Design can be
downloaded here.
These documents are provided as a guide to ADA contrast
ONLY and
is not legally binding. Rowmark established these guides using
the U.S.
Department of Justice ADA Standards for Accessible Design Title III,
section 4.30.5, which reads:
"*4.30.5 Finish and Contrast. The characters and background of signs
shall be eggshell, matte, or other non-glare finish. Characters and
symbols shall contrast with their background --either light characters
on a dark background or dark characters on a light background."
Please consult with the U.S. Department of Justice to ensure that your
signs are ADA compliant.
Website:
http://www.ada.gov.
Phone: 800-514-0301
The following guides are provided by using
the Light Reflectance Value measurement. See below for more
information about Light Reflectance Value:
As a courtesy to our customers,
Rowmark provides are findings for Light Reflectance Value of our Rowmark
ADA compliant materials.
Light Reflectance
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.
B1
= 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.
Test Results
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
recommended.
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.
