diff --git a/core/test/src/com/google/zxing/BufferedImageLuminanceSource.java b/core/test/src/com/google/zxing/BufferedImageLuminanceSource.java
index f22268674..5c8e40b26 100644
--- a/core/test/src/com/google/zxing/BufferedImageLuminanceSource.java
+++ b/core/test/src/com/google/zxing/BufferedImageLuminanceSource.java
@@ -49,12 +49,19 @@ public final class BufferedImageLuminanceSource extends LuminanceSource {
     // The color of fully-transparent pixels is irrelevant. They are often, technically, fully-transparent
     // black (0 alpha, and then 0 RGB). They are often used, of course as the "white" area in a
     // barcode image. Force any such pixel to be white:
+    int[] buffer = new int[width];
     for (int y = top; y < top + height; y++) {
-      for (int x = left; x < left + width; x++) {
-        if ((image.getRGB(x, y) & 0xFF000000) == 0) {
-          image.setRGB(x, y, 0xFFFFFFFF); // = white
+      image.getRGB(left, y, width, 1, buffer, 0, sourceWidth);
+      boolean rowChanged = false;
+      for (int x = 0; x < width; x++) {
+        if ((buffer[x] & 0xFF000000) == 0) {
+          buffer[x] = 0xFFFFFFFF; // = white
+          rowChanged = true;
         }
       }
+      if (rowChanged) {
+        image.setRGB(left, y, width, 1, buffer, 0, sourceWidth);
+      }
     }
 
     // Create a grayscale copy, no need to calculate the luminance manually
diff --git a/javase/src/com/google/zxing/client/j2se/BufferedImageLuminanceSource.java b/javase/src/com/google/zxing/client/j2se/BufferedImageLuminanceSource.java
index 0775703ab..aed8385a9 100644
--- a/javase/src/com/google/zxing/client/j2se/BufferedImageLuminanceSource.java
+++ b/javase/src/com/google/zxing/client/j2se/BufferedImageLuminanceSource.java
@@ -51,12 +51,19 @@ public final class BufferedImageLuminanceSource extends LuminanceSource {
     // The color of fully-transparent pixels is irrelevant. They are often, technically, fully-transparent
     // black (0 alpha, and then 0 RGB). They are often used, of course as the "white" area in a
     // barcode image. Force any such pixel to be white:
+    int[] buffer = new int[width];
     for (int y = top; y < top + height; y++) {
-      for (int x = left; x < left + width; x++) {
-        if ((image.getRGB(x, y) & 0xFF000000) == 0) {
-          image.setRGB(x, y, 0xFFFFFFFF); // = white
+      image.getRGB(left, y, width, 1, buffer, 0, sourceWidth);
+      boolean rowChanged = false;
+      for (int x = 0; x < width; x++) {
+        if ((buffer[x] & 0xFF000000) == 0) {
+          buffer[x] = 0xFFFFFFFF; // = white
+          rowChanged = true;
         }
       }
+      if (rowChanged) {
+        image.setRGB(left, y, width, 1, buffer, 0, sourceWidth);
+      }
     }
 
     // Create a grayscale copy, no need to calculate the luminance manually