Customarily, the primary colors of the visible spectrum were red, orange, yellow, green, blue, and violet. However, around 300 years ago, Sir Isaac Newton found another, situated between blue and violet, and named it what?

Sir Isaac Newton's groundbreaking experiments with prisms in the late 17th century revolutionized our understanding of light and color. Before his work, it was commonly believed that prisms somehow "colored" light. However, Newton demonstrated that white light is actually composed of a spectrum of colors, which are separated when passed through a prism. He meticulously observed and documented this phenomenon, identifying what he considered to be seven distinct colors: red, orange, yellow, green, blue, indigo, and violet.

The inclusion of indigo as a distinct color, situated between blue and violet, is a fascinating aspect of Newton's work. While many cultures and earlier scientists recognized a range of colors in the rainbow, Newton's decision to name and include seven specific colors is often attributed to his interest in numerology and the ancient Greek musical scale, which also has seven notes. He believed there was a harmonious relationship between the colors of the spectrum and musical intervals. Today, while we still acknowledge the continuous nature of the spectrum, indigo remains a recognized hue within the traditional mnemonic for the visible light spectrum, ROYGBIV, a testament to Newton's enduring influence on how we categorize and understand light.