Molten Orange vs Dull Red

How close are they?

ΔE 8.1, close: similar, with a visible difference side by side. Dull Red is a little lighter, more muted than Molten Orange.

Can I use Dull Red instead of Molten Orange?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Dull Red is a little lighter, more muted than Molten Orange.

Can I use Molten Orange instead of Dull Red?

The same difference applies the other way round: Molten Orange is a little darker, more saturated.

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.