Naphthol Red Light vs Mahogany Ink

How close are they?

ΔE 45.7, loose: different enough that you should pick on purpose. Mahogany Ink is noticeably darker, much more muted than Naphthol Red Light.

Can I use Mahogany Ink instead of Naphthol Red Light?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 46). Mahogany Ink is noticeably darker, much more muted than Naphthol Red Light.

Can I use Naphthol Red Light instead of Mahogany Ink?

The same difference applies the other way round: Naphthol Red Light is noticeably lighter, much 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.