Sunpetal vs Marigold Yellow

How close are they?

ΔE 43.0, loose: different enough that you should pick on purpose. Marigold Yellow is noticeably darker, much more muted, warmer than Sunpetal.

Can I use Marigold Yellow instead of Sunpetal?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 43). Marigold Yellow is noticeably darker, much more muted, warmer than Sunpetal.

Can I use Sunpetal instead of Marigold Yellow?

The same difference applies the other way round: Sunpetal is noticeably lighter, much more saturated, 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.