diff --git a/src/core/transformations/conversion_grayscale.cpp b/src/core/transformations/conversion_grayscale.cpp
index 7cc66cb..28e5f50 100644
--- a/src/core/transformations/conversion_grayscale.cpp
+++ b/src/core/transformations/conversion_grayscale.cpp
@@ -21,11 +21,27 @@ PNM* ConversionGrayscale::transform()
 
     if (image->format() == QImage::Format_Mono)
     {
-
+        for (int y = 0; y < height; ++y)
+        {
+            for (int x = 0; x < width; ++x)
+            {
+                QRgb pixel = image->pixel(x, y);
+                int gray = qGray(pixel);
+                newImage->setPixel(x, y, qRgb(gray, gray, gray));
+            }
+        }
     }
     else // if (image->format() == QImage::Format_RGB32)
     {
-
+        for (int y = 0; y < height; ++y)
+        {
+            for (int x = 0; x < width; ++x)
+            {
+                QRgb pixel = image->pixel(x, y);
+                int gray = qGray(pixel);
+                newImage->setPixel(x, y, qRgb(gray, gray, gray));
+            }
+        }
     }
 
     return newImage;