2 different recipes. Brands sell different pigment mixtures under this name, so they won't all look or mix alike. Compare the pigments below; the most common is PR101 Red Iron Oxide.
Who makes it
PR101 Red Iron Oxide5
- Holbein Artists' Oil Color No. H340
- PR101LF I OpaqueSeries 140 ml tube · 150 ml tube · 300 ml cartridge · 500 ml tin · 1000 ml tin* · 4000 ml tin*About Art Spectrum
PR102 Red Ochre / Burnt Sienna1
- Blockx Extra-Fine Oil Colours No. 212123
Sizes are the ones each line is sold in; marks a size only some colors come in. Check the store for a particular color.