IJA #3 Hairanshoku (Grey Indigo) vs Neutral Grey

How close are they?

ΔE 6.2, close: similar, with a visible difference side by side. Neutral Grey is more muted than IJA #3 Hairanshoku (Grey Indigo).

Can I use Neutral Grey instead of IJA #3 Hairanshoku (Grey Indigo)?

Usually, if you are not matching paint already on the model. Close match (ΔE 6). Neutral Grey is more muted than IJA #3 Hairanshoku (Grey Indigo).

Can I use IJA #3 Hairanshoku (Grey Indigo) instead of Neutral Grey?

The same difference applies the other way round: IJA #3 Hairanshoku (Grey Indigo) is 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.