diff --git a/Magick++/lib/Drawable.cpp b/Magick++/lib/Drawable.cpp
index a081663..fda0a73 100644
--- a/Magick++/lib/Drawable.cpp
+++ b/Magick++/lib/Drawable.cpp
@@ -633,7 +633,7 @@
 }
 Magick::DrawableFont::DrawableFont ( const std::string &family_,
                                      Magick::StyleType style_,
-                                     const size_t weight_,
+                                     const unsigned int weight_,
                                      Magick::StretchType stretch_ )
   : _font(),
     _family(family_),
diff --git a/Magick++/lib/Image.cpp b/Magick++/lib/Image.cpp
index b3f3f68..70ffef8 100644
--- a/Magick++/lib/Image.cpp
+++ b/Magick++/lib/Image.cpp
@@ -2875,10 +2875,10 @@
       ssize_t y_resolution=72;
 
       if (constImage()->x_resolution > 0.0)
-        x_resolution=static_cast<size_t>(constImage()->x_resolution + 0.5);
+        x_resolution=static_cast<ssize_t>(constImage()->x_resolution + 0.5);
 
       if (constImage()->y_resolution > 0.0)
-        y_resolution=static_cast<size_t>(constImage()->y_resolution + 0.5);
+        y_resolution=static_cast<ssize_t>(constImage()->y_resolution + 0.5);
 
       return Geometry(x_resolution,y_resolution);
     }
diff --git a/Magick++/lib/Magick++/Drawable.h b/Magick++/lib/Magick++/Drawable.h
index 3fdc1d5..768e0bc 100644
--- a/Magick++/lib/Magick++/Drawable.h
+++ b/Magick++/lib/Magick++/Drawable.h
@@ -934,7 +934,7 @@
 
   DrawableFont ( const std::string &family_,
                  StyleType style_,
-                 const size_t weight_,
+                 const unsigned int weight_,
                  StretchType stretch_ );
   DrawableFont ( const DrawableFont& original_ );
 
diff --git a/Magick++/lib/Magick++/STL.h b/Magick++/lib/Magick++/STL.h
index 2b9317c..94d9920 100644
--- a/Magick++/lib/Magick++/STL.h
+++ b/Magick++/lib/Magick++/STL.h
@@ -822,7 +822,7 @@
     void operator()( Image &image_ ) const;
 
   private:
-    size_t _opacity;
+    unsigned int _opacity;
   };
 
   // Change color of opaque pixel to specified pen color.