Genuine Naples yellow comes in several varieties and can range from a pastel true yellow (think cadmium yellow mixed with white) to a complex light brown. PY41 refers to the toxic lead color and has inspired a myriad of less-toxic blends to approximate it.
Usually when one sees imitation blends, these are named Hue as in Naples Yellow Hue, but this is not the case with Naples Yellow. Genuine Naples Yellow has been gone for so long and the blends are popular enough that this name space has taken on a life of its own. So when one sees a paint tube named "Naples Yellow" it is almost always a convenience blend. We counted about 54 different combinations for blends that approximate this color in oils alone.
Genuine Naples Yellow PY41, known as Giallorino, or Antimony Yellow, is a single-pigment toxic lead-based yellow. In color it ranges from a fairly opaque middle yellow with fairly high chroma to caramel brown. The age old question is do you need the "real thing"?
There are a couple of shades of this color which can be found at Natural Pigments. We've tried a handful of these in our historical color quests. We started with a caramel brown version of this color and branched out into other kinds.
While it is interesting in mixes, its toxicity is a huge drawback. Monona Rossol's work has a section on health problems from lead as well as antimony in pigments in the Artist's Guide to Health and Safety. Her most recent research can be found through her site. Lead is toxic, and even though Naples Yellow Genuine is great for portraiture, we avoid lead in the studio and haven't missed it.
Genuine Naples yellow tends to require a medium amount of oil, which is interesting in comparison to Lead White which requires very little. Naples Yellow Genuine has a fairly fast drying time, though some have felt it was more of a medium drying time - opinions differ a bit. It is also a heavy pigment.
