Troglodyte Blue vs True Blue

How close are they?

ΔE 17.5, loose: different enough that you should pick on purpose. True Blue is a little darker, more saturated, warmer than Troglodyte Blue.

Can I use True Blue instead of Troglodyte Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). True Blue is a little darker, more saturated, warmer than Troglodyte Blue.

Can I use Troglodyte Blue instead of True Blue?

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