...

diff --git a/MagickCore/enhance.c b/MagickCore/enhance.c
index aa30f6143b4526aec9d111304eb6958b803afaba..f74ed80b1e535c2687a29a026a67eece2d4832fa 100644 (file)
--- a/MagickCore/enhance.c
+++ b/MagickCore/enhance.c
@@ -3317,6 +3317,11 @@ MagickExport MagickBooleanType ModulateImage(Image *image,const char *modulate,
         green,
         red;
 
+      if (GetPixelReadMask(image,q) == 0)
+        {
+          q+=GetPixelChannels(image);
+          continue;
+        }
       red=(double) GetPixelRed(image,q);
       green=(double) GetPixelGreen(image,q);
       blue=(double) GetPixelBlue(image,q);