diff --git a/skimage/filters/thresholding.py b/skimage/filters/thresholding.py
index d21bd579..285af6d4 100644
--- a/skimage/filters/thresholding.py
+++ b/skimage/filters/thresholding.py
@@ -134,8 +134,8 @@ def threshold_otsu(image, nbins=256):
     # Check if the image is multi-colored or not
     if image.min() == image.max():
         raise ValueError("threshold_otsu is expected to work with images " \
-                        "having more than one color. The input image seems " \
-                        "to have just one color {0}.".format(image.min()))
+                         "having more than one color. The input image seems " \
+                         "to have just one color {0}.".format(image.min()))
 
     hist, bin_centers = histogram(image.ravel(), nbins)
     hist = hist.astype(float)