Gypsum White vs White Grey

How close are they?

ΔE 9.9, close: similar, with a visible difference side by side. White Grey is a little lighter, more saturated than Gypsum White.

Can I use White Grey instead of Gypsum White?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). White Grey is a little lighter, more saturated than Gypsum White.

Can I use Gypsum White instead of White Grey?

The same difference applies the other way round: Gypsum White is a little darker, 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.