Some humans enjoy tetrachromacy. There's an article floating around where one such woman mentions that in her world she sees mismatched colors everywhere; colors that to everybody else look identical (e.g. on a shirt and pants, or two walls) but which to her look different, sometimes significantly. IIRC, the fourth spectrum peak isn't that far away from one of the others, so I assume this effect is probably exaggerated by artificial dyes that reflect in relatively narrow bands.

EDIT: Here's the reported anecdote I was remembering:

> "I have always had polite disagreements with people about shades of colours," she says. When clothes shopping for instance, she often finds that apparently matching tops and skirts seem to be a different shade to her, clashing horribly--even though no one else seems to notice it. Her sensitivity can sometimes be baffling to those around: when helping to restore a house, she once rejected 32 paint samples before settling on the right shade. "The beiges were too yellow and not blue enough, not cool enough; some of the almonds were too orangey," she says--distinctions that were much to the confusion of her building contractor.

https://www.bbc.com/future/article/20140905-the-women-with-s...

There are also rumors that tetrachomats are sought after as snipers, since camouflage often doesn't fool them at all.

It's a lot more complicated than RGB buckets, there is a serie of preprocessing cells https://en.wikipedia.org/wiki/Retinal_ganglion_cell before the image "signal" is further processed by the visual cortex.

Another species could have the exact same "buckets" configuration and perceive color differently if the ganglionic layer is connected differently to those buckets.

However, the processing after the cone cells can't introduce any new information. It just creates a new coordinate system on the 3-dimensional space described by the cone cells.