Those particular signs have an insert that goes inside, there isn't one in it right now, that's why there isn't any contrast.
These signs are for a Healthcare organization tied to the ACA that recently acquired a large building that used to be Blue Cross... kind of ironic.
Most of the ADA signs are non compliant. One of their newly hired HR people purchased them for the entire facility only to find they didn't pass upon inspection of the building department.
Oh well, lots of interior signs to replace. There's one of these places just about every mile apart!