Green Base vs Death Guard Green

How close are they?

ΔE 8.9, close: similar, with a visible difference side by side. Death Guard Green is a little lighter, warmer than Green Base.

Can I use Death Guard Green instead of Green Base?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Death Guard Green is a little lighter, warmer than Green Base.

Can I use Green Base instead of Death Guard Green?

The same difference applies the other way round: Green Base is a little darker, cooler.

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.