Dechala Lilac vs Pilgrim Grey

How close are they?

ΔE 34.4, loose: different enough that you should pick on purpose. Pilgrim Grey is a little darker, much more muted than Dechala Lilac.

Can I use Pilgrim Grey instead of Dechala Lilac?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 34). Pilgrim Grey is a little darker, much more muted than Dechala Lilac.

Can I use Dechala Lilac instead of Pilgrim Grey?

The same difference applies the other way round: Dechala Lilac is a little 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.