Shadow Blue vs IDF Blue

How close are they?

ΔE 10.8, fair: the same colour family, but not a straight swap. IDF Blue is a little lighter, more saturated than Shadow Blue.

Can I use IDF Blue instead of Shadow Blue?

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

Can I use Shadow Blue instead of IDF Blue?

The same difference applies the other way round: Shadow Blue is a little darker, more muted.

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.