Purple Alchemy vs Magos Purple

How close are they?

ΔE 31.5, loose: different enough that you should pick on purpose. Magos Purple is a little lighter, much more muted, cooler than Purple Alchemy.

Can I use Magos Purple instead of Purple Alchemy?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 32). Magos Purple is a little lighter, much more muted, cooler than Purple Alchemy.

Can I use Purple Alchemy instead of Magos Purple?

The same difference applies the other way round: Purple Alchemy is a little darker, much 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.