Pastel Indigo vs Grey Spell

How close are they?

ΔE 16.6, loose: different enough that you should pick on purpose. Grey Spell is noticeably darker, more muted, warmer than Pastel Indigo.

Can I use Grey Spell instead of Pastel Indigo?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Grey Spell is noticeably darker, more muted, warmer than Pastel Indigo.

Can I use Pastel Indigo instead of Grey Spell?

The same difference applies the other way round: Pastel Indigo 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.