diff --git a/css-color-5/Overview.bs b/css-color-5/Overview.bs
index c8c2289c0a7..4abf7dafd88 100644
--- a/css-color-5/Overview.bs
+++ b/css-color-5/Overview.bs
@@ -1588,6 +1588,7 @@ the allowed [=channel keywords=] are:
 	are all <<number>>s
 	that correspond to the [=origin color's=] red, green, and blue channels
 	after <a href="#required-conversion">conversion, if required</a> to the predefined RGB color space.
+	The value 1.0 corresponds to 100%.
 
 Within a [=relative color=] syntax ''color()'' function using <<xyz-params>>,
 the allowed [=channel keywords=] are:
@@ -1596,6 +1597,7 @@ the allowed [=channel keywords=] are:
 	that correspond to the [=origin color's=] X, Y and Z channels
 	after <a href="#required-conversion">conversion, if required</a> to relative CIE XYZ color space
 	adapted to the relevant white point.
+	The value 1.0 corresponds to 100%.
 
 Within a [=relative color=] syntax ''color()'' function 
 using either <<predefined-rgb-params>> or