Castellax Bronze vs Chaos Bronze

How close are they?

ΔE 22.3, loose: different enough that you should pick on purpose. Chaos Bronze is noticeably lighter, much more muted, cooler than Castellax Bronze.

Can I use Chaos Bronze instead of Castellax Bronze?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Chaos Bronze is noticeably lighter, much more muted, cooler than Castellax Bronze.

Can I use Castellax Bronze instead of Chaos Bronze?

The same difference applies the other way round: Castellax Bronze is noticeably darker, much more saturated, warmer.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.