diff --git a/lessons/4-ComputerVision/06-IntroCV/OpenCV.ipynb b/lessons/4-ComputerVision/06-IntroCV/OpenCV.ipynb
index 5727e736..3c999709 100644
--- a/lessons/4-ComputerVision/06-IntroCV/OpenCV.ipynb
+++ b/lessons/4-ComputerVision/06-IntroCV/OpenCV.ipynb
@@ -135,7 +135,7 @@
    "source": [
     "bw_im = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)\n",
     "print(bw_im.shape)\n",
-    "plt.imshow(bw_im)"
+    "plt.imshow(bw_im, cmap='gray')"
    ]
   },
   {