The rainbow closet is everywhere — reds together, then oranges, yellows, greens, blues, on down the line. It photographs beautifully. It also does almost nothing to help you get dressed faster, and most people who try it figure that out within a week.
Why color-only sorting doesn't solve the real problem
Sorting purely by color answers one question: what colors do I own? It doesn't answer the question you actually face every morning, which is what goes with what. A navy blouse sitting next to a navy skirt tells you nothing about whether they work as an outfit — they're only next to each other because they share a color, not because they belong together. You still have to do the pairing work yourself, standing there, running through combinations in your head.
The structure that actually works: category first, color second
Color sorting isn't wrong — it's just missing a layer. Sort by category first — Top, Bottom, Extra — so every piece is already grouped with the things it could realistically pair with. Then, within each of those three lists, arrange by color. Now a scan down your Top list shows you every top in roughly the order you'd reach for it, and pairing becomes a matter of matching colors within a system that's already organized around outfits, not just hues.
Putting it into practice
Pull everything out of the closet and make three piles on the bed: Top, Bottom, Extra. Don't think about color yet — just sort by function. Once every piece has a pile, go back through each pile and arrange it lightest to darkest, or however you naturally think about color. Hang it back up in that order. The rainbow effect still happens — it just happens inside a structure that's actually built for getting dressed, not just for looking tidy.