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 + PY42 Yellow Iron Oxide.
Who makes it
PR101 Red Iron Oxide + PY42 Yellow Iron Oxide2
- Rembrandt Artists' Oil Colour No. 273PY42 PR101LF I TransparentSeries 315 ml tube · 40 ml tube · 60 ml tube* · 150 ml tube*About Rembrandt
- Schmincke Mussini Resin-Oil No. 10237
PR101 Red Iron Oxide1
- PR101LF I TransparentSeries 240 ml tube · 150 ml tube · 300 ml cartridge · 500 ml tin · 1000 ml tin* · 4000 ml tin*About Art Spectrum
Sizes are the ones each line is sold in; marks a size only some colors come in. Check the store for a particular color.