Questions:

1. Name the class of pigments that impart a yellow colour to pumpkins, egg yolk, canaries, and daffodils, among other naturally occurring life-forms. Flamingoes also get their characteristic pink hue by consuming food containing pigments of this class.

2. Two colours are said to be complementary if, when they are mixed, the result is a greyscale colour. In the RGB colour scheme – which uses red, green, and blue as the primary colours – what is the complementary colour of yellow?

3. During the Mughal period in India, a pigment called Indian yellow was used to render a vivid yellow colour in paintings and frescoes, especially when viewed under sunlight. Name the acid whose salts are the primary components of this pigment.

4. Name the chemical compound responsible for the yellow-red hues of saffron dye. Studies have found this compound has anti-inflammatory properties, as well as a potential ability to disrupt processes involved in the progression of Alzheimer’s.

5. Chrome yellow is a popular yellow pigment, and was particularly so in the 19th century. Its principal component is the compound ____ ________. A French chemist discovered this fact when he was studying a naturally occurring form of the compound called crocoite. Fill in the blanks.

Visual:

Name the yellow pigment derived from trees of the family Guttiferae (shown). This pigment’s name is derived from an older name for the country where these trees grow. FOREST & KIM STARR

Answers:

1. Carotenoids

2. Blue

3. Euxanthic acid

4. Crocin

5. Lead chromate

Visual: Gamboge (from Cambodia)