Hoplite Gold vs Tropical Green

How close are they?

ΔE 27.6, loose: different enough that you should pick on purpose. Tropical Green is a little lighter, more saturated, cooler than Hoplite Gold.

Can I use Tropical Green instead of Hoplite Gold?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 28). Tropical Green is a little lighter, more saturated, cooler than Hoplite Gold.

Can I use Hoplite Gold instead of Tropical Green?

The same difference applies the other way round: Hoplite Gold 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.