Fluor Rose vs Fresh Blood

How close are they?

ΔE 36.2, loose: different enough that you should pick on purpose. Fresh Blood is a little darker, much more saturated, warmer than Fluor Rose.

Can I use Fresh Blood instead of Fluor Rose?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 36). Fresh Blood is a little darker, much more saturated, warmer than Fluor Rose.

Can I use Fluor Rose instead of Fresh Blood?

The same difference applies the other way round: Fluor Rose is a little lighter, much more muted, 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.