Label1.text="Textfarbe"
 Dim c As Color = Label1.BackColor, c1 As Color
 c1 = Color.FromArgb(c.ToArgb Xor Color.White.ToArgb) 'Die Komplementärfarbe 
 ' per XOR

dim a as integer=50
If Abs(Int(c.R) - Int(c1.R)) < a And Abs(Int(c.G) - Int(c1.G)) < a Then _
  'unterscheiden sich Rot- und Grünanteil zu wenig voneinander
c1 = Color.Red
End If
Label1.ForeColor = c1

Dont debug, because there will allways be one more bug