diff --git a/color.h b/color.h
index 4e0b86d..6434d90 100644
--- a/color.h
+++ b/color.h
@@ -2,6 +2,7 @@
 #define COLOR_H
 
 #include <iostream>
+#include <cmath>
 
 #include "vec3.h"
 #include "util.h"
@@ -12,9 +13,9 @@ void write_color(std::ostream &out, Color pixel_color, int sample_per_pixel) {
     auto b = pixel_color.z();
 
     auto scale = 1.0 / sample_per_pixel;
-    r *= scale;
-    g *= scale;
-    b *= scale;
+    r = std::sqrt(scale * r);
+    g = std::sqrt(scale * g);
+    b = std::sqrt(scale * b);
 
     out << static_cast<int>(256 * clamp(r, 0.0, 0.999)) << " "
         << static_cast<int>(256 * clamp(g, 0.0, 0.999)) << " "