Sulfuryellow

Sulfuryellow, also known as sulfur yellow, is a historical pigment name used for yellow pigments derived from arsenic sulfide minerals, most notably orpiment (arsenic trisulfide, As2S3). The term has been applied to describe bright yellow pigments containing arsenic sulfide and is sometimes equated with orpiment-based colorants.

Chemically, sulfuryellow pigments are based on arsenic sulfides and are valued for their vivid yellow hue. However, they are highly toxic due to the arsenic content. They are also relatively unstable in light and air, and can darken or alter tone over time, especially with exposure to oxidizing conditions. Handling and storage require care, as with other arsenic-containing substances.

Historically, sulfuryellow was used in various periods of art and illumination, including medieval and early modern painting, as a colorant in pigments and glazes. It could appear either as a pure pigment or in mixtures with binders and other colors. In the spectrum of arsenic sulfide pigments, realgar (AsS) provides orange to red hues, while orpiment furnishes the characteristic yellow.

Modern practice has largely abandoned sulfuryellow pigments because of toxicity and stability concerns. They have been supplanted by safer and more durable yellows, such as Naples yellow (lead antimonate), various cadmium yellows, and modern organic yellows. In cases where historical works may contain orpiment or related pigments, conservation and handling follow strict safety protocols to manage arsenic-related risks.

See also: Orpiment, Realgar, Naples yellow, Hansa Yellow.