Green Uniform Base vs Caliban Green

How close are they?

ΔE 15.5, loose: different enough that you should pick on purpose. Caliban Green is a little lighter, more saturated, cooler than Green Uniform Base.

Can I use Caliban Green instead of Green Uniform Base?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Caliban Green is a little lighter, more saturated, cooler than Green Uniform Base.

Can I use Green Uniform Base instead of Caliban Green?

The same difference applies the other way round: Green Uniform Base 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.