Stained Ivory vs Light Brown

How close are they?

ΔE 7.7, close: similar, with a visible difference side by side. Light Brown is a little darker, more muted than Stained Ivory.

Can I use Light Brown instead of Stained Ivory?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Light Brown is a little darker, more muted than Stained Ivory.

Can I use Stained Ivory instead of Light Brown?

The same difference applies the other way round: Stained Ivory is a little lighter, more saturated.

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.