Skyshard vs Fang White

How close are they?

ΔE 18.4, loose: different enough that you should pick on purpose. Fang White is a little lighter, more saturated than Skyshard.

Can I use Fang White instead of Skyshard?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Fang White is a little lighter, more saturated than Skyshard.

Can I use Skyshard instead of Fang White?

The same difference applies the other way round: Skyshard is a little 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.