1. Red: Represents loyalty, bravery, righteousness, and passion. It is often used for heroic characters, such as generals and warriors, as well as for characters with strong positive emotions.
2. Black: Symbolises seriousness, integrity, impartiality, and authority. It is commonly used for upright officials, judges, and other characters with a strong sense of justice.
3. White: Denotes treachery, cunning, deceit, and evil. It is typically used for villainous characters, such as scheming ministers or corrupt officials.
4. Blue: Represents calmness, serenity, and trustworthiness. It is often used for wise scholars, loyal ministers, and other characters with a calm and composed demeanour.
5. Green: Symbolises youth, vitality, vigour, and sometimes jealousy. It is commonly used for young male characters, such as warriors or martial artists, as well as for female characters with a strong personality.
6. Yellow: Traditionally represents royalty, power, and wealth. It is often used for emperors, kings, and other noble characters, as well as for characters with a sense of authority and majesty.
7. Purple: Signifies mystery, magic, and otherworldly powers. It is typically used for supernatural beings, such as gods, demons, or immortals, and for characters with mystical abilities.
8. Gold and Silver: These colours are used to represent wealth, grandeur, and luxury. They are commonly found in the costumes and masks of wealthy characters or those of high status.
It's important to note that the specific meanings and symbolism of colours can vary slightly depending on the particular opera style or region, but these are the general associations associated with each colour in Chinese opera masks.