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
PR101 Red Iron Oxide + PY42 Yellow Iron Oxide1
- Williamsburg Handmade Oil Colors No. 6001474PY42 PR101LF I Semi-transparentSeries 437 ml tube · 150 ml tube · 8 fl oz can* · 16 fl oz can*About Williamsburg
PY83 Diarylide Yellow HR1
- PY83LF I TransparentSeries 340 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.