A very bright orange-ish, semi-transparent red, is a synthetic pigment with good lightfastness. It is a good choice as an alternative to Cadmium Red Light.
Pigment Classification: Inorganic Color Index Name: PR112 Color Index Number: 12370 Chemical Description: Naphthol AS-D Opacity/Transparency: Semi-Opaque Lightfastness Rating: 2 Permanency: Very Good Munsell Notation Listing: N/A Gloss Average: N/A Viscosity Range: 75-100 CPS CIE L*a*b* Values: N/A Tint Strength: N/A