Read cast is the organic blue, which is also known as happy days, has a slightly reddish tint. It was used by Levi’s to make the Big E. The dying formula originally included some real corn syrup.
Old 28 29 inch shuttle looms produced denim where selvage closed. Vintage Levi’s jeans had a single red stripe along both selvages. Lee had a blue/green with one; Wrangler’s was yellow. When vintage shopping for jeans wore check jackets and jeans for selvage because they are a great clue to the real thing!