diff --git a/noise.cpp b/noise.cpp
index c509149d..3a121ef4 100644
--- a/noise.cpp
+++ b/noise.cpp
@@ -29,14 +29,13 @@ util::noise::image2d (uint8_t *restrict pixels,
                       size_t            width,
                       size_t            height,
                       const util::noise::fractal &p) {
-    util::range<double> r(0.0,0.0);
+    util::range<double> r(std::numeric_limits<double>::quiet_NaN (),
+                          std::numeric_limits<double>::quiet_NaN ());
 
     for (size_t y = 0; y < height; ++y)
         for (size_t x = 0; x < width; ++x) {
-            double v = p.eval (x / double (width) * 2, y / double (height) * 2);
+            double v = p.eval (x / double (width), y / double (height));
             r.expand (v);
-            v += 1.0;
-            v /= 2.0;
             pixels[x + y * width] = v * std::numeric_limits<uint8_t>::max ();
         }