protected override Rgb ToRgb()
 {
     var hRad = H * System.Math.PI / 180.0;
     var lab = new Lab
     {
         L = L,
         A = System.Math.Cos(hRad) * C,
         B = System.Math.Sin(hRad) * C
     };
     return lab.ToColorSpace<Rgb>();
 }