Dorn Yellow vs Hansa Yellow Opaque

How close are they?

ΔE 15.5, loose: different enough that you should pick on purpose. Hansa Yellow Opaque is a little lighter, more saturated, cooler than Dorn Yellow.

Can I use Hansa Yellow Opaque instead of Dorn Yellow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Hansa Yellow Opaque is a little lighter, more saturated, cooler than Dorn Yellow.

Can I use Dorn Yellow instead of Hansa Yellow Opaque?

The same difference applies the other way round: Dorn Yellow is a little darker, more muted, 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.