(To clarify: Colour does not encode copyright information; it encodes provenance, intent and related ideas. Child porn is only a somewhat special case in the sense that laws are very insensitive about the shade of colour here. Usually, if it looks enough like CP, a possessor will end up in trouble, regardless of whether it's actual CP or whether they can prove they created it ex nihilo in MS Paint. But that's because child abuse is considered by societies worldwide a special kind of evil that needs extraordinary measures to combat. In almost all other cases, courts are very sensitive to the shades of colour.)
(To clarify: Colour does not encode copyright information; it encodes provenance, intent and related ideas. Child porn is only a somewhat special case in the sense that laws are very insensitive about the shade of colour here. Usually, if it looks enough like CP, a possessor will end up in trouble, regardless of whether it's actual CP or whether they can prove they created it ex nihilo in MS Paint. But that's because child abuse is considered by societies worldwide a special kind of evil that needs extraordinary measures to combat. In almost all other cases, courts are very sensitive to the shades of colour.)