Dorn Yellow vs Arylide Yellow Deep

How close are they?

ΔE 16.3, loose: different enough that you should pick on purpose. Arylide Yellow Deep is a little darker, warmer than Dorn Yellow.

Can I use Arylide Yellow Deep instead of Dorn Yellow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Arylide Yellow Deep is a little darker, warmer than Dorn Yellow.

Can I use Dorn Yellow instead of Arylide Yellow Deep?

The same difference applies the other way round: Dorn Yellow is a little lighter, cooler.

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.