Aesthetic neutrality
Neutrals and their colour
Neutrals are real colour
AV blue is a neutral
As much as a sheep skin is a neutral
Neutrality as in a minimal amount of energy exchanged to produce.
In the case of colour, neutrality would be the naturally occurring with little effort. This excludes colours produced on instance for mating rituals, camouflage or other denfense or attack purposes.
Neutral colours would be
Silence in Paul as a neutral
Ambient noise as neutral
Relating to neutral colour