Sacred Scarlet vs Pumpkin

How close are they?

ΔE 15.8, loose: different enough that you should pick on purpose. Pumpkin is noticeably lighter, more muted than Sacred Scarlet.

Can I use Pumpkin instead of Sacred Scarlet?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Pumpkin is noticeably lighter, more muted than Sacred Scarlet.

Can I use Sacred Scarlet instead of Pumpkin?

The same difference applies the other way round: Sacred Scarlet is noticeably 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.