diff --git a/magick/cache.c b/magick/cache.c
index cdd9a6c..4f39ee1 100644
--- a/magick/cache.c
+++ b/magick/cache.c
@@ -2231,6 +2231,8 @@
       */
       image->taint=MagickTrue;
       image->type=UndefinedType;
+      if (image->colorspace == GRAYColorspace)
+        image->colorspace=RGBColorspace;
       if (ValidatePixelCacheMorphology(image) == MagickFalse)
         status=OpenPixelCache(image,IOMode,exception);
     }