--- a/Image.st	Tue Feb 21 15:02:39 2017 +0100
+++ b/Image.st	Tue Feb 21 17:23:36 2017 +0100
@@ -13528,7 +13528,8 @@
 !
 
 alphaShiftForPixelValue
-    "return the shift amount used with translation from pixelValues to alphaBits"
+    "return the shift amount used with translation from pixelValues to alphaBits.
+     That is the number of bits to shift the alpha value into the pixel value."
 
     |redBits greenBits blueBits|
 
@@ -13537,10 +13538,12 @@
         greenBits := bitsPerSample at:2.
         blueBits := bitsPerSample at:3.
 
-        ^ (greenBits + blueBits + redBits) negated
+        ^ (greenBits + blueBits + redBits)
     ].
 
     self subclassResponsibility
+
+    "Modified: / 21-02-2017 / 16:41:42 / cg"
 !
 
 ascentOn:aGC