Our dyes are created based on the premise that they will dye white or light colored fabric the color of the dye.  So when our Black or Graphite dye is applied to a colored fabric, the original color of the fabric may still show through. To address this, we recommend adding an additional color (per our chart here) to counteract the undertones of the existing color. As an example, if you were dyeing red fabric, we would recommend adding some green dye to your dyebath. Since mixing red and green makes black, adding a green dye to your dyebath will counteract the red on the fabric.