Acid Yellow 40 is an acid dye from the pyrazolone class, known for its bright, clean, greenish-yellow colour. It is used for dyeing natural protein fibres and for many industrial colouring applications. With its excellent water solubility and good levelling properties, it is easy to work with and produces even, consistent shades. It is known for fashion textiles, leather goods, and specialty papers where a vibrant, eye-catching yellow is desired.
