diff --git a/src/core/transformations/histogram_stretching.cpp b/src/core/transformations/histogram_stretching.cpp
index b865773..2a03e5d 100644
--- a/src/core/transformations/histogram_stretching.cpp
+++ b/src/core/transformations/histogram_stretching.cpp
@@ -20,42 +20,76 @@ PNM* HistogramStretching::transform()
     PNM* newImage = new PNM(width, height, image->format());
     Histogram* histogram = image->getHistogram();
 
-    int minValue = -1;
-    int maxValue = -1;
+    int maxRed = 255, maxGreen = 255, maxBlue = 255, maxGrey = 255;
 
-    for (int y = 0; y < image->height(); ++y) {
-        for (int x = 0; x < image->width(); ++x) {
-            if (histogram->get(Histogram::LChannel)->value(x + y * x) != 0)
-            {
-                minValue = histogram->get(Histogram::LChannel)->value(x + y * x);
-                break;
-            }
+    int minRed = 0, minGreen = 0, minBlue = 0, minGrey = 0;
+
+    QHash<int, int>* R = histogram->get(histogram->RChannel);
+    QHash<int, int>* G = histogram->get(histogram->GChannel);
+    QHash<int, int>* B = histogram->get(histogram->BChannel);
+    QHash<int, int>* L = histogram->get(histogram->LChannel);
+
+    for (int i=0; i<256; i++)
+    {
+        if (R->value(minRed) == 0) {
+            minRed++;
+        }
+
+        if (G->value(minGreen) == 0) {
+            minGreen++;
+        }
+
+        if (B->value(minBlue) == 0) {
+            minBlue++;
+        }
+
+        if (L->value(minGrey) == 0) {
+            minGrey++;
         }
     }
 
-    for (int y = image->height(); y > 0; --y) {
-        for (int x = image->width(); x < 0; --x) {
-            if (histogram->get(Histogram::LChannel)->value(x + y * x) != 0)
-            {
-                minValue = histogram->get(Histogram::LChannel)->value(x + y * x);
-                break;
-            }
+    for (int i=256; i>0; i--)
+    {
+        if (R->value(maxRed) == 0) {
+            maxRed--;
+        }
+
+        if (G->value(maxGreen) == 0) {
+            maxGreen--;
+        }
+
+        if (B->value(maxBlue) == 0) {
+            maxBlue--;
+        }
+
+        if (L->value(maxGrey) == 0) {
+            maxGrey--;
         }
     }
 
-    for (int y = 0; y < image->height(); ++y) {
-        for (int x = 0; x < image->width(); ++x) {
-            QRgb pixel = image->pixel(x, y);
+    for (int x = 0; x < image->width(); x++) {
+        for (int y = 0; y < image->height(); y++) {
+           QRgb p = image->pixel(x, y);
 
-            int red = qRed(pixel);
-            int green = qGreen(pixel);
-            int blue = qBlue(pixel);
+           if(image->format() == QImage::Format_RGB32) {
+               int red = qRed(p);
+               int green = qGreen(p);
+               int blue = qBlue(p);
 
-            int stretchedRed = (255 * (red - minValue)) / (maxValue - minValue);
-            int stretchedGreen = (255 * (green - minValue)) / (maxValue - minValue);
-            int stretchedBlue = (255 * (blue - minValue)) / (maxValue - minValue);
-
-            newImage->setPixel(x, y, qRgb(stretchedRed, stretchedGreen, stretchedBlue));
+               newImage->setPixel(
+                           x,
+                           y,
+                           QColor(
+                               (255 / (maxRed - minRed)) * (red - minRed),
+                               (255 / (maxGreen - minGreen)) * (green - minGreen),
+                               (255 / (maxBlue - minBlue)) * (blue - minBlue)
+                           ).rgb());
+           } else {
+               newImage->setPixel(
+                           x,
+                           y,
+                           (255 / (maxGrey - minGrey)) * (qGray(p) - minGrey));
+           }
         }
     }