Hobgoblin Hue vs Bright Ivory

How close are they?

ΔE 7.6, close: similar, with a visible difference side by side. Bright Ivory is a little lighter, cooler than Hobgoblin Hue.

Can I use Bright Ivory instead of Hobgoblin Hue?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Bright Ivory is a little lighter, cooler than Hobgoblin Hue.

Can I use Hobgoblin Hue instead of Bright Ivory?

The same difference applies the other way round: Hobgoblin Hue 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.