Naples yellow was historically made from lead-tin yellow (PY41), a toxic pigment that has fallen out of favor since the late 19th century when synthetic replacements began to overtake it. Presently, watercolors sold as Naples Yellow are either mixes (usually involving cadmium orange and white), or they’re made from PBr24. That’s what I’ll be looking at today. It’s an opaque, butter-yellow pigment that looks to me like a brighter version of Yellow Ochre.