rainbow spectrum color guide: violet, indigo, blue, green, yellow, orange, red

color chart spectrum violet indigo blue green yellow orange red visual display rainbow guide block label vertical background border graphic palette bright vibrant primary secondary tertiary design art education learning reference tool hue shade tone contrast light arrangement sequence order gradient information diagram template layout format sample representation symbol sign concept educational visualize teach instruct demonstrate identify recognize understand learn knowledge colorful brightness saturation intensity color-coding categorize organize visual aid teaching resource informative instructional classroom study academic school lesson