Warpfiend Grey vs Silver Grey

How close are they?

ΔE 17.5, loose: different enough that you should pick on purpose. Silver Grey is a little darker, more muted, cooler than Warpfiend Grey.

Can I use Silver Grey instead of Warpfiend Grey?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Silver Grey is a little darker, more muted, cooler than Warpfiend Grey.

Can I use Warpfiend Grey instead of Silver Grey?

The same difference applies the other way round: Warpfiend Grey is a little lighter, more saturated, warmer.

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.