Cobalt Turquois vs Light Turquoise

How close are they?

ΔE 15.3, loose: different enough that you should pick on purpose. Light Turquoise is a little lighter, more saturated, cooler than Cobalt Turquois.

Can I use Light Turquoise instead of Cobalt Turquois?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Light Turquoise is a little lighter, more saturated, cooler than Cobalt Turquois.

Can I use Cobalt Turquois instead of Light Turquoise?

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