Yes, sunlight plus a good prism, inside a box with a pinhole, projecting on white paper. Or a room with a window that faces the sun, covered except for a pinhol

Yes, sunlight plus a good prism, inside a box with a pinhole, projecting on white paper. Or a room with a window that faces the sun, covered except for a pinhole, projecting on a whitewashed wall. Which is what Newton did, or so I've read. Anyway, when I do that, my moderate red-green color blindness is obvious. Because there's a gap in the spectrum. But on a good computer display, there's far less of a gap, because colors aren't spectral, just mixed. For example: https://www.deviantart.com/0bsidianfire/art/Sanguine-467600743 https://www.deviantart.com/0bsidianfire/art/Sanguine-4676007...