Paint mixing –
I'm not sure where you went to get the mixture, but there are shades of marroon and burgundy in most paint chips. All kinds of tint goes in to shift the end color. Red Oxide, Blue, Even Green to get rid of some of the red.
I would go to a paint store that is more commercial. There they have people bring things in all the time and say can you match this?
Personally I like Marroon (a solvent base) in "One Shot" brand sign paint. It is becoming hard to find. You can really thin it down as it is concentrated and make it run or leave it thick. A very little can (4oz) will go a long long way.
Even a magenta would be shifted toward purple with blue (slightly) then some green to get that bright red pigment to turn more brown.
Look in the designer colors at any home store. I think I saw a rustoleum burgundy that would possibly work. In acrylics, the colors get a little muddy when shifted off of a true pigment color like Magenta. In a color pallet, acrylics are usually sort of pastel and every bold color is a synthetic tint that produces just that standard color.
But, again the real paint players might be able to hook you up.
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