ΔE 12.0, fair: the same colour family, but not a straight swap. Barley Gray BS4800/18B21 is a little lighter, more muted, cooler than Hydra Turquoise.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Barley Gray BS4800/18B21 is a little lighter, more muted, cooler than Hydra Turquoise.
The same difference applies the other way round: Hydra Turquoise is a little darker, more saturated, warmer.
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.
See Hydra Turquoise on the colour wheel See Barley Gray BS4800/18B21 on the colour wheel
All matches: Hydra Turquoise equivalents · Barley Gray BS4800/18B21 equivalents