Blue Horror vs The White

How close are they?

ΔE 24.7, loose: different enough that you should pick on purpose. The White is noticeably lighter, much more muted than Blue Horror.

Can I use The White instead of Blue Horror?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). The White is noticeably lighter, much more muted than Blue Horror.

Can I use Blue Horror instead of The White?

The same difference applies the other way round: Blue Horror is noticeably darker, much 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.