In the end, all colours come from nature. How would we know how to create such tones if we hadn´t seen them in the natural world? Magenta, ochre, verdant green, cool grey?
How would art know where to start, if not from nature? In many ways, can we say that visual forms, by their very being, are natural?
Is art really an unconscious exercise of trying to catch something natural in a represented form, so that the creation itself takes on something of nature?
In the end, all colour comes from nature.