Phthalo Turquoise Light vs Sombre Grey

How close are they?

ΔE 14.8, fair: the same colour family, but not a straight swap. Sombre Grey is more muted, warmer than Phthalo Turquoise Light.

Can I use Sombre Grey instead of Phthalo Turquoise Light?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Sombre Grey is more muted, warmer than Phthalo Turquoise Light.

Can I use Phthalo Turquoise Light instead of Sombre Grey?

The same difference applies the other way round: Phthalo Turquoise Light is 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.