Задание цвета через RGB

e.Graphics.DrawEllipse(Pens.Purple, (float)(pictureBox1.Width / 10 + j * WStep), (float)(pictureBox1.Height / 10 + i * HStep),60,40);

Color.FromArgb(1, Convert.ToInt32(Math.Abs(P1[i, j])), 0, 0)

e.Graphics.DrawEllipse(new Pen(Color.FromArgb(Red,Green,Blue),width), (float)(pictureBox1.Width / 10 + j * WStep), (float)(pictureBox1.Height / 10 + i * HStep),60,40);

private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.DrawLine(Pens.Black, pictureBox1.Width / 10, pictureBox1.Height / 20, pictureBox1.Width / 10, 19 * pictureBox1.Height / 20);
    e.Graphics.DrawLine(Pens.Black, pictureBox1.Width / 20, 9 * pictureBox1.Height / 10, 19 * pictureBox1.Width / 20, 9 * pictureBox1.Height / 10);
    double HStep;
    double WStep;
    int diam = Math.Min(pictureBox1.Width / 10, pictureBox1.Height / 10);
   
    HStep = (8 * pictureBox1.Height) / ((N + 2) * 15);
    WStep = (8 * pictureBox1.Width) / ((N + 2) * 15);
    for (i = 0; i < N + 1; i++)
    {
        for (j = 0; j < N + 1; j++)
        {
            
            //Pen myPen = new Pen(Color.FromArgb(1, Convert.ToInt32(Math.Abs(P1[i, j])), 0, 0));
            e.Graphics.DrawEllipse(Pens.Blue, (float)(pictureBox1.Width / 10 + j * WStep) + (float)diam*2 , (float)(pictureBox1.Height / 10 + i * HStep) + (float)diam*2, diam, diam);
          }
    }
}