Dark Tone vs Petroleum Brown Wash

How close are they?

ΔE 16.1, loose: different enough that you should pick on purpose. Petroleum Brown Wash is noticeably lighter, more saturated than Dark Tone.

Can I use Petroleum Brown Wash instead of Dark Tone?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Petroleum Brown Wash is noticeably lighter, more saturated than Dark Tone.

Can I use Dark Tone instead of Petroleum Brown Wash?

The same difference applies the other way round: Dark Tone is noticeably darker, more muted.

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.