Fire Giant Orange vs Marigold Yellow

How close are they?

ΔE 17.5, loose: different enough that you should pick on purpose. Marigold Yellow is a little lighter, more muted, cooler than Fire Giant Orange. They are different kinds of paint: Army Painter Fire Giant Orange is a one-coat contrast-style paint and Reaper Marigold Yellow is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.

Can I use Marigold Yellow instead of Fire Giant Orange?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Marigold Yellow is a little lighter, more muted, cooler than Fire Giant Orange. They are different kinds of paint.

Can I use Fire Giant Orange instead of Marigold Yellow?

The same difference applies the other way round: Fire Giant Orange is a little darker, 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.