     public func convertFromXYZ(_ color: XYZColorModel) -> Model {
         let s = 216.0 / 24389.0
         let t = 24389.0 / 27.0
+        let white = cieXYZ.normalized.white.point
         let _white = XYZColorModel(luminance: 1, x: white.x, y: white.y)
         let x = color.x / _white.x
         let y = color.y / _white.y

        let x = fx3 > s ? fx3 : t * (116 * fx - 16)
        let y = color.lightness > st ? fy * fy * fy : t * color.lightness
        let z = fz3 > s ? fz3 : t * (116 * fz - 16)
        let _white = XYZColorModel(luminance: 1, x: white.x, y: white.y)
        return XYZColorModel(x: x * _white.x, y: y * _white.y, z: z * _white.z)
    }

    public func convertFromXYZ(_ color: XYZColorModel) -> Model {
        let s = 216.0 / 24389.0
        let t = 24389.0 / 27.0
        let white = cieXYZ.normalized.white.point
        let _white = XYZColorModel(luminance: 1, x: white.x, y: white.y)
        let m = 1 / (color.x + 15 * color.y + 3 * color.z)
        let n = 1 / (_white.x + 15 * _white.y + 3 * _white.z)
