Luminous Orange vs IJA Chrome Yellow

How close are they?

ΔE 15.2, loose: different enough that you should pick on purpose. IJA Chrome Yellow is a little lighter, cooler than Luminous Orange.

Can I use IJA Chrome Yellow instead of Luminous Orange?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). IJA Chrome Yellow is a little lighter, cooler than Luminous Orange.

Can I use Luminous Orange instead of IJA Chrome Yellow?

The same difference applies the other way round: Luminous Orange is a little darker, warmer.

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.