Periwinkle Purple vs Gloomy Violet

How close are they?

ΔE 25.7, loose: different enough that you should pick on purpose. Gloomy Violet is noticeably darker, much more muted, warmer than Periwinkle Purple.

Can I use Gloomy Violet instead of Periwinkle Purple?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Gloomy Violet is noticeably darker, much more muted, warmer than Periwinkle Purple.

Can I use Periwinkle Purple instead of Gloomy Violet?

The same difference applies the other way round: Periwinkle Purple is noticeably lighter, much more saturated, cooler.

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.