Matplotlib plots lose transparency when saving as .pdf

I'm seeing exactly the same issue as this one: Matplotlib Plots Lose Transparency When Saving as .ps/.eps except I am trying to output to PDF rather than ps/eps. The answers to the previous question point out that eps does not support transparency and suggest either rasterising or saving as a PDF. I do get correct looking output when I save as png, so it seems as though matplotlib is dealing with the transparency correctly, but the backend is failing. Clearly PDF does support transparency, so it's not a problem with the format I'm trying to use. I'm running in OS X (Yosemite) with the default MacOSX matplotlib backend and using matplotlib 1.4.1. Is there any reason why this setup should fail to produce transparent PDF output? This used to work in the past (with OS X Mavericks and an earlier version of matplotlib) but I'm not sure exactly what change has caused this problem. If the following code is run, the problem can be seen in with_hatch.pdf, but not in any of the other output files. ``` #! /usr/bin/env python import matplotlib.pyplot as plt fig = plt.figure( figsize=(6, 6), dpi=100, facecolor='white' ) ax = fig.add_axes( [0.15, 0.1, 0.8, 0.85] ) bin_edges = [0.0, 0.5, 0.5, 1.0, 1.0, 1.5, 1.5, 2.0, 2.0, 2.5, 2.5, 3.0, 3.0, 3.5, 3.5, 4.0, 4.0, 4.5, 4.5, 5.0, 5.0, 5.5, 5.5, 6.0, 6.0, 7.0, 7.0, 8.0] y_low = [0.9581631739289882, 0.9581631739289882, 0.8966054746563691, 0.8966054746563691, 0.8369962202270926, 0.8369962202270926, 0.7824880045351325, 0.7824880045351325, 0.7231695683685057, 0.7231695683685057, 0.6673767757896321, 0.6673767757896321, 0.6083447707111752, 0.6083447707111752, 0.5602384968623321, 0.5602384968623321, 0.5109567893600544, 0.5109567893600544, 0.4707872827805316, 0.4707872827805316, 0.4304527769718274, 0.4304527769718274, 0.39024135798617826, 0.39024135798617826, 0.3593458738615755, 0.3593458738615755, 0.3275704585658484, 0.3275704585658484] y_high = [0.9762065896798683, 0.9762065896798683, 0.9227253843496172, 0.9227253843496172, 0.8738222849514, 0.8738222849514, 0.8299500683866315, 0.8299500683866315, 0.7810616940586165, 0.7810616940586165, 0.7357506442258693, 0.7357506442258693, 0.6852756294051707, 0.6852756294051707, 0.6441575476130643, 0.6441575476130643, 0.5987788803224889, 0.5987788803224889, 0.5630257208701298, 0.5630257208701298, 0.5274860424153797, 0.5274860424153797, 0.4915335923551736, 0.4915335923551736, 0.46502435263727837, 0.46502435263727837, 0.43196895235913746, 0.43196895235913746] ax.fill_between( bin_edges, y_low, y_high, facecolor='green', edgecolor='white', alpha=0.4 ) plt.savefig( 'without_hatch.pdf' ) plt.savefig( 'without_hatch.png' ) ax.fill_between( bin_edges, y_low, y_high, facecolor='green', edgecolor='white', hatch='xxxx', alpha=0.4 ) plt.savefig( 'with_hatch.pdf' ) plt.savefig( 'with_hatch.png' ) ``` Now submitted to matplotlib bug tracker at: https://github.com/matplotlib/matplotlib/issues/3841