diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
index da643f96b94f..13b0480579ae 100644
--- a/lib/matplotlib/tests/test_axes.py
+++ b/lib/matplotlib/tests/test_axes.py
@@ -29,8 +29,6 @@
 import warnings
 from matplotlib.cbook import IgnoredKeywordWarning
 
-import sys
-on_win = (sys.platform == 'win32')
 
 # Note: Some test cases are run twice: once normally and once with labeled data
 #       These two must be defined in the same test function or need to have
@@ -2766,7 +2764,7 @@ def test_subplot_key_hash():
 @image_comparison(baseline_images=['specgram_freqs',
                                    'specgram_freqs_linear'],
                   remove_text=True, extensions=['png'],
-                  tol=0.07 if on_win else 0.03)
+                  tol=0.07)
 def test_specgram_freqs():
     '''test axes.specgram in default (psd) mode with sinusoidal stimuli'''
     n = 10000
@@ -2867,7 +2865,7 @@ def test_specgram_noise():
 @image_comparison(baseline_images=['specgram_magnitude_freqs',
                                    'specgram_magnitude_freqs_linear'],
                   remove_text=True, extensions=['png'],
-                  tol=0.07 if on_win else 0.03)
+                  tol=0.07)
 def test_specgram_magnitude_freqs():
     '''test axes.specgram in magnitude mode with sinusoidal stimuli'''
     n = 10000
@@ -2969,7 +2967,7 @@ def test_specgram_magnitude_noise():
 
 @image_comparison(baseline_images=['specgram_angle_freqs'],
                   remove_text=True, extensions=['png'],
-                  tol=0.007 if on_win else 0)
+                  tol=0.007)
 def test_specgram_angle_freqs():
     '''test axes.specgram in angle mode with sinusoidal stimuli'''
     n = 10000
diff --git a/lib/matplotlib/tests/test_patheffects.py b/lib/matplotlib/tests/test_patheffects.py
index c9ff921a1a2b..b9ece19b36ef 100644
--- a/lib/matplotlib/tests/test_patheffects.py
+++ b/lib/matplotlib/tests/test_patheffects.py
@@ -17,9 +17,6 @@
     import mock
 from nose.tools import assert_equal
 
-import sys
-on_win = (sys.platform == 'win32')
-
 
 @image_comparison(baseline_images=['patheffect1'], remove_text=True)
 def test_patheffect1():
@@ -113,7 +110,7 @@ def test_SimplePatchShadow_offset():
     assert_equal(pe._offset, (4, 5))
 
 
-@image_comparison(baseline_images=['collection'], tol=0.013 if on_win else 0)
+@image_comparison(baseline_images=['collection'], tol=0.015)
 def test_collection():
     x, y = np.meshgrid(np.linspace(0, 10, 150), np.linspace(-5, 5, 100))
     data = np.sin(x) + np.cos(y)
diff --git a/lib/mpl_toolkits/tests/test_mplot3d.py b/lib/mpl_toolkits/tests/test_mplot3d.py
index 86f62af9fd8f..3eaa8fd74821 100644
--- a/lib/mpl_toolkits/tests/test_mplot3d.py
+++ b/lib/mpl_toolkits/tests/test_mplot3d.py
@@ -149,7 +149,7 @@ def test_text3d():
     ax.set_zlabel('Z axis')
 
 
-@image_comparison(baseline_images=['trisurf3d'], remove_text=True)
+@image_comparison(baseline_images=['trisurf3d'], remove_text=True, tol=0.03)
 def test_trisurf3d():
     n_angles = 36
     n_radii = 8