Yellow is the color between orange and green that is most luminous and captures attention. It is used for caution signs and emergency vehicles because the human eye processes yellow first. The oldest yellow pigments were yellow ochre and orpiment, while later Europeans used lead tin yellow and imported Indian yellow. Yellow has various shades and is associated with sunshine, knowledge, and life, but also autumn and maturity. It can be used in business for children's products, in fast food to encourage eating and leaving quickly, and in interior design, fashion, and furniture for its energizing effects.