What Percentage do discrete TGSI’s need to be?

Architects, Designers and the like often fall into the trap of specifying the individual tactile dots. These individual tactile dots are called discrete tactiles. Discrete tactiles are required by AS1428.4.1 – 2009 to have a minimum allowable luminance contrast ratio of 45%.

This usually catches people out as most people know about the 30% contrast ratio but haven’t come across the 45% or the 60% (composite discrete tactiles) requirements.

For example, see pictures below of where these discrete tactiles do not have sufficient contrast ratios.