In BV1 Indigo we find an Deep, Deep Blue, which sits just after leaving Royal Blue headed towards Violet, but stopping before it turns into a true Blue Violet.
As we add Red to Blue, it begins to cascade in the Blue Violet section of the wheel. Meaning, as we head towards Violet, darker colors begin to have a Violet character, while the same color if lightened, appears with a distinct Blue character for much longer. It’s a weird, tricky, but strikingly beautiful color, Blue Violet.
Indigo is one of the 7 colors of the Rainbow (ROYGBIV) and is distinct from both Primary and Sky Blue, but still lacks enough Red to present with any really clear Violet warmth coming through.
Sapphire(9) is a beautiful, intense, ethereal, deep, night sky, old and rich feeling Blue, so we call it our Indigo. It has its own mixing group to reinforce that it is not Blue or Blue Violet, it’s Indigo. It has its own unique energy which is deep, bold, and powerful. It is hard to get this mood out of any other blue, or even any other color, on the color wheel.
I use it often to deepen Blues or pull Violets towards Blue, infusing them with Indigo’s powerful mood. It’s my go-to for desaturating Oranges and Golden Yellows, when I want as much rich Indigo energy to come through in my shadows as possible.