Webbing Khaki vs Nickel Azo Yellow

How close are they?

ΔE 15.1, loose: different enough that you should pick on purpose. Nickel Azo Yellow is a little darker, much more saturated than Webbing Khaki.

Can I use Nickel Azo Yellow instead of Webbing Khaki?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Nickel Azo Yellow is a little darker, much more saturated than Webbing Khaki.

Can I use Webbing Khaki instead of Nickel Azo Yellow?

The same difference applies the other way round: Webbing Khaki is a little lighter, much more muted.

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.