Field Grey Base #1 (Green uniform) vs N.

How close are they?

ΔE 3.8, very close: most people won’t see a difference side by side. N. is a little lighter than Field Grey Base #1 (Green uniform).

Can I use N. instead of Field Grey Base #1 (Green uniform)?

Yes, for most jobs. Very close match (ΔE 4). N. is a little lighter than Field Grey Base #1 (Green uniform).

Can I use Field Grey Base #1 (Green uniform) instead of N.?

The same difference applies the other way round: Field Grey Base #1 (Green uniform) is a little darker.

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.