private void RotateColors(Bitmap image, float degrees)
{
	ImageAttributes imageAttributes = new ImageAttributes();
	int width = image.Width;
	int height = image.Height;
	double r = degrees * System.Math.PI / 180; // degrees to radians
	float cosR = (float)Math.Cos(r);
	float sinR = (float)Math.Sin(r);
	float a = (1 + 2 * cosR) / 3;
	float b = ((1 - cosR) - (float)Math.Sqrt(3) * sinR) / 3;
	float c = ((1 - cosR) + (float)Math.Sqrt(3) * sinR) / 3;

	float[][] colorMatrixElements = { 
		new float[] {a, b, c, 0, 0},
		new float[] {c, a, b, 0, 0},
		new float[] {b, c, a, 0, 0},
		new float[] {0, 0, 0, 1, 0},
		new float[] {0, 0, 0, 0, 1}};

	ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements);
	
	imageAttributes.SetColorMatrix(
	   colorMatrix,
	   ColorMatrixFlag.Default,
	   ColorAdjustType.Bitmap);

	using (Graphics g = Graphics.FromImage(image))
	{
		g.DrawImage(
		   image,
		   new Rectangle(0, 0, width, height),  // destination rectangle 
			0, 0,        // upper-left corner of source rectangle 
			width,       // width of source rectangle
			height,      // height of source rectangle
			GraphicsUnit.Pixel,
		   imageAttributes);
	}
}