Some of the brighter clan setts are sometimes referred to as the dress
tartan to distinguish them from the darker tartans of the same name.
However, in speaking of dress tartans we generally mean those generated
from darker designs. For example, the Royal Stewart will have the plain
red under check changed to white in Stewart Dress.
A Campbell design will have one blue undercheck replaced by white.
The result can be seen as an attempt to adapt existing darker designs
to look like the white setts used for the arisaids, formerly worn by Highland
ladies. The result is then for both men and women as "evening dress".
Whilst these arisaid setts were not clan designs, the combination of a
clan tartan with an arisaid type of design is essentially modern and some
clan chiefs do not recognise the Dress form of their tartans.
Since tartans were originally a functional outdoor cloth, the dress tartans
are a product of emerging social patterns.