Light Grey Shadow vs Grey Castle

How close are they?

ΔE 11.0, fair: the same colour family, but not a straight swap. Grey Castle is a little lighter than Light Grey Shadow.

Can I use Grey Castle instead of Light Grey Shadow?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Grey Castle is a little lighter than Light Grey Shadow.

Can I use Light Grey Shadow instead of Grey Castle?

The same difference applies the other way round: Light Grey Shadow is a little darker.

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.