Blood Red Skies vs Light Orange

How close are they?

ΔE 26.7, loose: different enough that you should pick on purpose. Light Orange is a little lighter, warmer than Blood Red Skies.

Can I use Light Orange instead of Blood Red Skies?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 27). Light Orange is a little lighter, warmer than Blood Red Skies.

Can I use Blood Red Skies instead of Light Orange?

The same difference applies the other way round: Blood Red Skies is a little darker, 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.