PY 109 – isoindole yellow

This isoindolinone class of pigments were developed in 1946 and commercially available in the 1960s

Manufacturer/ product code:  Kremer / 23340
Chemical Description:  isoindolinone
Color: yellow
Color Index: PY 109
Date:  from 1964

PY 109 – Isoindole Yellow is a synthetic organic pigment belonging to the isoindoline family, a class of high-performance yellow pigments renowned for their excellent lightfastness, chemical stability, and vibrant hue. PY 109 is characterized by a clear, warm yellow with a slightly reddish undertone, offering high chromatic purity and versatility in both artistic and industrial applications.

Chemically, PY 109 is based on the isoindoline molecular structure, which consists of fused aromatic rings containing nitrogen atoms that confer exceptional resistance to light, heat, and chemical attack. This stability makes it suitable for demanding industrial applications, including automotive coatings, plastics, printing inks, and high-performance paints, as well as for artists’ materials requiring long-term color permanence.

In artistic applications, Isoindole Yellow exhibits high tinting strength and semi-opaque to transparent properties, depending on particle size and formulation. It mixes cleanly with other yellows, oranges, and reds to produce a wide range of warm tones, and its transparency allows for glazing and layering techniques in oil, acrylic, and watercolor media. Its relatively neutral warm undertone makes it ideal for producing both bright and subtle yellow shades without overpowering other colors in a mixture.

From a conservation standpoint, PY 109 is highly stable and chemically inert, retaining its hue and chromatic clarity over extended periods.