How to add watermark to PrintDocument
PrintDocument printDoc = new PrintDocument();
printDoc.PrintPage += new PrintPageEventHandler(printDoc_PrintPage);
textControl1.PrintPreview(printDoc);
Graphics g = e.Graphics;
g.TranslateTransform(200, 200);
g.RotateTransform(e.PageSettings.Landscape ? 30 : 60);
g.DrawString("DRAFT VERSION", new Font("Arial", 20, FontStyle.Bold),
new SolidBrush(Color.FromArgb(64, Color.Black)), 0, 0);
source: http://www.textcontrol.com/downloads/library/printing/watermarks/