diff --git a/src/main/java/org/apache/commons/sanselan/formats/png/BitParser.java b/src/main/java/org/apache/commons/sanselan/formats/png/BitParser.java
index 3c46117..84ca18c 100644
--- a/src/main/java/org/apache/commons/sanselan/formats/png/BitParser.java
+++ b/src/main/java/org/apache/commons/sanselan/formats/png/BitParser.java
@@ -63,7 +63,7 @@
 
         int rot = 8 - bitDepth;
         if (rot > 0)
-            sample <<= rot;
+            sample = sample * 255 / ((1 << bitDepth) - 1);
         else if (rot < 0)
             sample >>= -rot;