Let’s do some sums on this…
A typical cinema white used to be 14 ft-Lamberts, which is a bit less than 50 nits. This is about the same light level you would get if the white screen was illuminated at 150 lux. Space is about 150 kLux, or about 1000x brighter. You can get the same lighting levels if you go 32x as far away from the sun. That gets you almost to the orbit of Neptune.
So, colours at the orbit of Neptune would be muted, but so are the colours in “The Wizard of Oz”. If you go 10x further out, you will be down to about 1 Lux, which is typical low lighting in conference centres, and you can still see colour.
