Hoplite Gold vs Retributor Armour

How close are they?

ΔE 15.2, loose: different enough that you should pick on purpose. Retributor Armour is a little darker, much more muted than Hoplite Gold.

Can I use Retributor Armour instead of Hoplite Gold?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Retributor Armour is a little darker, much more muted than Hoplite Gold.

Can I use Hoplite Gold instead of Retributor Armour?

The same difference applies the other way round: Hoplite Gold is a little lighter, much more saturated.

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.