Yellow produces a warming effect, arouses cheerfulness, stimulates mental activity, and generates muscle energy. Yellow is often associated with food. Bright, pure yellow is an attention getter, which is the reason taxicabs are painted this color. Yellow is seen before other colors when placed against black; this combination is often used to issue a warning. In heraldry, yellow indicates honor and loyalty. Use yellow to evoke pleasant, cheerful feelings. Yellow is very effective for attracting attention, so use it to highlight the most important elements of your design. Light yellow tends to disappear into white, so it usually needs a dark color to highlight it.