Leafy Green vs Light Green (Blue Shade)

How close are they?

ΔE 18.9, loose: different enough that you should pick on purpose. Light Green (Blue Shade) is a little lighter, cooler than Leafy Green.

Can I use Light Green (Blue Shade) instead of Leafy Green?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Light Green (Blue Shade) is a little lighter, cooler than Leafy Green.

Can I use Leafy Green instead of Light Green (Blue Shade)?

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