Piggy Purple Ink vs Ink Magenta

How close are they?

ΔE 43.0, loose: different enough that you should pick on purpose. Ink Magenta is much more saturated, warmer than Piggy Purple Ink.

Can I use Ink Magenta instead of Piggy Purple Ink?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 43). Ink Magenta is much more saturated, warmer than Piggy Purple Ink.

Can I use Piggy Purple Ink instead of Ink Magenta?

The same difference applies the other way round: Piggy Purple Ink is much more muted, 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.