Soft Tone vs Hazard Yellow Wash

How close are they?

ΔE 45.5, loose: different enough that you should pick on purpose. Hazard Yellow Wash is noticeably lighter, much more muted, cooler than Soft Tone.

Can I use Hazard Yellow Wash instead of Soft Tone?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 46). Hazard Yellow Wash is noticeably lighter, much more muted, cooler than Soft Tone.

Can I use Soft Tone instead of Hazard Yellow Wash?

The same difference applies the other way round: Soft Tone is noticeably darker, much 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.