Using Fonts in System with iTextSharp

1st you need to register the font and then just retrieve it from the FontFactory (and don't create it every time):

public static iTextSharp.text.Font GetTahoma()
{
    var fontName = "Tahoma";
    if (!FontFactory.IsRegistered(fontName))
    {
         var fontPath = Environment.GetEnvironmentVariable("SystemRoot") + "\\fonts\\tahoma.ttf";
         FontFactory.Register(fontPath,fontName);
    }
    return FontFactory.GetFont(fontName, BaseFont.IDENTITY_H, BaseFont.EMBEDDED); 
}

I ended up combining the 2 answers here into this method:

public static Font GetFont(string fontName, string filename)
{
    if (!FontFactory.IsRegistered(fontName))
    {
        var fontPath = Environment.GetEnvironmentVariable("SystemRoot") + "\\fonts\\" + filename;
        FontFactory.Register(fontPath);
    }
    return FontFactory.GetFont(fontName, BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
}

Which I then use in my code like so:

writer.DirectContent.SetFontAndSize(GetFont("Franklin Gothic Medium Cond", "FRAMDCN.TTF").BaseFont, 24f);

On Windows you can find out the font's file name from the font's property sheet:

I also found that you have to use the font's exact name on the Details tab: