SINGLE-CHANNEL DISTINCTION
Two categories are separated by one property, and that property is not available to everyone.
01 DEFINITION
Condition in which a distinction that carries consequence rests on a single perceptual channel, so it fails for operators whose access to that channel differs and under conditions that degrade it.
02 CONDITIONS
03 WHERE IT APPEARS
04 WHAT AEON WORKED THROUGH HERE
It arrived as a request to add a second channel where categories were separated by hue alone. Underneath was a harder finding: the layout had already spent its redundancy elsewhere, so the second channel could not be added — it had to be taken from something. Deciding where it is owed and where it is decoration was the work.
The question it keeps returning to is how a second channel is added without the first becoming decorative — redundancy that is ignored is not redundancy.