Vulcan Orange vs Sunny Skin Tone

How close are they?

ΔE 18.7, loose: different enough that you should pick on purpose. Sunny Skin Tone is noticeably lighter, more saturated than Vulcan Orange.

Can I use Sunny Skin Tone instead of Vulcan Orange?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Sunny Skin Tone is noticeably lighter, more saturated than Vulcan Orange.

Can I use Vulcan Orange instead of Sunny Skin Tone?

The same difference applies the other way round: Vulcan Orange 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.