ΔE 7.8, close: similar, with a visible difference side by side. Signal Blue is a little darker, more muted than Payne’s Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Signal Blue is a little darker, more muted than Payne’s Grey.
The same difference applies the other way round: Payne’s Grey is a little lighter, more saturated.
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 Payne’s Grey on the colour wheel See Signal Blue on the colour wheel
All matches: Payne’s Grey equivalents · Signal Blue equivalents