Magecast Magenta vs Royal Purple

How close are they?

ΔE 6.9, close: similar, with a visible difference side by side. Royal Purple is a little darker than Magecast Magenta.

Can I use Royal Purple instead of Magecast Magenta?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Royal Purple is a little darker than Magecast Magenta.

Can I use Magecast Magenta instead of Royal Purple?

The same difference applies the other way round: Magecast Magenta is a little lighter.

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.