Colour might, however, play an important role in helping to ensure that the sign is noticed in the first place. It should contrast in colour from the surface it is mounted on. Likewise, the legend should contrast in colour and in brightness from its immediate background. Some believe that North Americans overuse red in signage and that people might dismiss red signs as part of the visual clutter of urban spaces. Others argue that we are more likely to notice red exit signs because that is what we are conditioned to see.
More research is required to settle the debate.
Meanwhile, I admit to particularly noticing the wild purple exit signs used throughout one building in Orlando, Florida. Legends and Arrows Text on exit signs should be as large as possible and the spacing between the characters should be reasonably wide. Many codes specify minimum letter height. Few discuss spacing between characters. Consequently, there exist signs with narrow characters crammed into the smallest space possible.