Sahara Yellow vs Ryza Rust

How close are they?

ΔE 17.0, loose: different enough that you should pick on purpose. Ryza Rust is noticeably darker, more saturated, warmer than Sahara Yellow.

Can I use Ryza Rust instead of Sahara Yellow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Ryza Rust is noticeably darker, more saturated, warmer than Sahara Yellow.

Can I use Sahara Yellow instead of Ryza Rust?

The same difference applies the other way round: Sahara Yellow is noticeably lighter, more muted, cooler.

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.