No, hair should not be washed any sooner than a day or two before applying dye. Though it may seem intuitive that hair free of product residue and oil would accept color more readily and evenly, the opposite is true. The natural oils that build up on the hair help the color grip the strands and act as a protective barrier for the scalp.
Additionally, the use of color-enhancing and color-depositing shampoos and treatments should be discontinued before consulting with a stylist. The true color of the hair must be assessed in order to select the right products and colors to achieve the desired result.