diff --git a/color_space.py b/color_space.py
index 1ce1cb0..3ade8ef 100644
--- a/color_space.py
+++ b/color_space.py
@@ -40,6 +40,7 @@ def to_HSV(I):
 def to_nRGB(I):
     _I = I / 255.0
     norm_I = numpy.sqrt(_I[:, :, 0] ** 2 + _I[:, :, 1] ** 2 + _I[:, :, 2] ** 2)
+    norm_I[norm_I == 0] = 1 / numpy.sqrt(3) # To avoid division by 0 below, set these pixels to normalized gray
     norm_r = (_I[:, :, 0] / norm_I * 255).astype(numpy.uint8)
     norm_g = (_I[:, :, 1] / norm_I * 255).astype(numpy.uint8)
     norm_b = (_I[:, :, 2] / norm_I * 255).astype(numpy.uint8)