ΔE 8.3, close: similar, with a visible difference side by side. Sanctuary Red is a little lighter, more saturated than Red Madder.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Sanctuary Red is a little lighter, more saturated than Red Madder.
The same difference applies the other way round: Red Madder is a little darker, 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.
See Red Madder on the colour wheel See Sanctuary Red on the colour wheel
All matches: Red Madder equivalents · Sanctuary Red equivalents