Rust Tone vs Berserker Bloodshade

How close are they?

ΔE 15.5, loose: different enough that you should pick on purpose. Berserker Bloodshade is a little lighter, more saturated, cooler than Rust Tone.

Can I use Berserker Bloodshade instead of Rust Tone?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Berserker Bloodshade is a little lighter, more saturated, cooler than Rust Tone.

Can I use Rust Tone instead of Berserker Bloodshade?

The same difference applies the other way round: Rust Tone is a little darker, more muted, 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.