2 different recipes. Brands sell different pigment mixtures under this name, so they won't all look or mix alike. Compare the pigments below.
Who makes it
PBk11 Mars Black + PR101 Red Iron Oxide + PY42 Yellow Iron Oxide1
- Williamsburg Handmade Oil Colors No. 6001021PY42 PBk11 PR101LF I OpaqueSeries 2Hue37 ml tube · 150 ml tube · 8 fl oz can* · 16 fl oz can*About Williamsburg
PBk11 Mars Black + PG7 Phthalo Green + PY42 Yellow Iron Oxide1
- Lukas 1862 Artists' Oil No. 0157
Sizes are the ones each line is sold in; marks a size only some colors come in. Check the store for a particular color.