Naphthol Pink vs Ink Red

How close are they?

ΔE 24.5, loose: different enough that you should pick on purpose. Ink Red is noticeably darker, more muted, warmer than Naphthol Pink.

Can I use Ink Red instead of Naphthol Pink?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Ink Red is noticeably darker, more muted, warmer than Naphthol Pink.

Can I use Naphthol Pink instead of Ink Red?

The same difference applies the other way round: Naphthol Pink is noticeably lighter, 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.