Gauss Green vs Iosan Green

How close are they?

ΔE 18.8, loose: different enough that you should pick on purpose. Iosan Green is a little darker, more muted, cooler than Gauss Green.

Can I use Iosan Green instead of Gauss Green?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Iosan Green is a little darker, more muted, cooler than Gauss Green.

Can I use Gauss Green instead of Iosan Green?

The same difference applies the other way round: Gauss Green is a little lighter, more saturated, 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.