Warp Lightning vs Yellow Green

How close are they?

ΔE 16.3, loose: different enough that you should pick on purpose. Yellow Green is a little lighter, more muted, warmer than Warp Lightning. They are different kinds of paint: Citadel Warp Lightning is a one-coat contrast-style paint and Tamiya Yellow Green is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.

Can I use Yellow Green instead of Warp Lightning?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Yellow Green is a little lighter, more muted, warmer than Warp Lightning. They are different kinds of paint.

Can I use Warp Lightning instead of Yellow Green?

The same difference applies the other way round: Warp Lightning is a little darker, more saturated, 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.