Titan Buff vs Light Blue

How close are they?

ΔE 17.2, loose: different enough that you should pick on purpose. Light Blue is noticeably darker, more muted, cooler than Titan Buff.

Can I use Light Blue instead of Titan Buff?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Light Blue is noticeably darker, more muted, cooler than Titan Buff.

Can I use Titan Buff instead of Light Blue?

The same difference applies the other way round: Titan Buff is noticeably 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.