Oil Stains vs Blue Liner

How close are they?

ΔE 8.1, close: similar, with a visible difference side by side. Blue Liner is a little darker, more saturated than Oil Stains.

Can I use Blue Liner instead of Oil Stains?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Blue Liner is a little darker, more saturated than Oil Stains.

Can I use Oil Stains instead of Blue Liner?

The same difference applies the other way round: Oil Stains is a little lighter, 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.