ΔE 9.4, close: similar, with a visible difference side by side. Liquid Mask is a little lighter than Gypsum White.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Liquid Mask is a little lighter than Gypsum White.
The same difference applies the other way round: Gypsum White 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.
See Gypsum White on the colour wheel See Liquid Mask on the colour wheel
All matches: Gypsum White equivalents · Liquid Mask equivalents