Light Yellow vs Hexos Palesun

How close are they?

ΔE 18.6, loose: different enough that you should pick on purpose. Hexos Palesun is noticeably lighter, more muted, cooler than Light Yellow.

Can I use Hexos Palesun instead of Light Yellow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Hexos Palesun is noticeably lighter, more muted, cooler than Light Yellow.

Can I use Light Yellow instead of Hexos Palesun?

The same difference applies the other way round: Light Yellow is noticeably darker, 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.