diff --git a/src/dotout.c b/src/dotout.c
index eea70a2..6a241e7 100644
--- a/src/dotout.c
+++ b/src/dotout.c
@@ -33,7 +33,6 @@ extern Role I_RRSD;
 #define RUNCOLORDELTA 0.2	// maximum hue delta between roles (0.2): smaller means role colors of a protocol become more similar.
 #define RUNCOLORCONTRACT 0.8	// contract from protocol edges: smaller means more distinction between protocols.
 #define UNTRUSTEDCOLORS 0.4
-#define MONOCHROMEFACTOR 0.7	// Monochrome settings. 0.0: all colors become white. 1.0: all colors remain the same lightness as the color versions.
 
 #define CHOOSEWEIGHT "2.0"
 #define RUNWEIGHT "10.0"
@@ -317,19 +316,33 @@ hlsrgbreal (int *r, int *g, int *b, double h, double l, double s)
 void
 hlsrgb (int *r, int *g, int *b, double h, double l, double s)
 {
+  double closer (double l, double factor)
+  {
+    return l + ((1.0 - l) * factor);
+  }
+
   if (switches.monochrome)
     {
-      // No colors: make lighter
+      // No colors
       s = 0;
       h = 0;
-      l = 1 - ((1 - l) * MONOCHROMEFACTOR);
-      hlsrgbreal (r, g, b, h, l, s);
     }
-  else
+
+  if (switches.lightness > 0)
     {
-      // colors
-      hlsrgbreal (r, g, b, h, l, s);
+      // correction switch for lightness
+      if (switches.lightness == 100)
+	{
+	  l = 1.0;
+	}
+      else
+	{
+	  l = closer (l, ((double) switches.lightness / 100.0));
+	}
     }
+
+// convert
+  hlsrgbreal (r, g, b, h, l, s);
 }
 
 
diff --git a/src/switches.c b/src/switches.c
index acdc766..d453805 100644
--- a/src/switches.c
+++ b/src/switches.c
@@ -78,6 +78,7 @@ switchesInit (int argc, char **argv)
   switches.extendTrivial = 0;	// default off
   switches.plain = false;	// default colors for terminal
   switches.monochrome = false;	// default colors for dot
+  switches.lightness = 0;	// lightness correction
   switches.clusters = false;	// default is no clusters for now
 
   // Process the environment variable SCYTHERFLAGS
@@ -908,6 +909,25 @@ switcher (const int process, int index, int commandline)
 	}
     }
 
+  if (detect (' ', "lightness", 1))
+    {
+      if (!process)
+	{
+	  /* discourage: hide
+	   */
+	}
+      else
+	{
+	  switches.lightness = integer_argument ();
+	  if ((switches.lightness < 0) || (switches.lightness > 100))
+	    {
+	      error
+		("--lightness=x only accepts integer values between 0 and 100");
+	    }
+	  return index;
+	}
+    }
+
   if (detect (' ', "clusters", 0))
     {
       if (!process)
diff --git a/src/switches.h b/src/switches.h
index 441eb15..4f280df 100644
--- a/src/switches.h
+++ b/src/switches.h
@@ -58,6 +58,7 @@ struct switchdata
   int extendTrivial;		//!< Show further events in arachne xml output, based on knowledge underapproximation. (Includes at least the events of the nonreads extension)
   int plain;			//!< Disable color output on terminal
   int monochrome;		//!< Disable colors in dot output
+  int lightness;		//!< Lightness increment 0-100
   int clusters;			//!> Enable clusters in output
 };