Weaving is like painting in some ways. Your warp and weft colors are like tubes of paint, giving you basic colors to start with. Your draft is like your palette and brush, where you take your original paint colors, mix them into new colors, and then place them in your fabric.
Often, when we think about color in weaving, we think only about the colors of the yarns we choose. But this is like thinking only about the colors in your paint tubes. We also need to think about how the drafts will mix the colors.