title: Python Matplotlib RC Parameters not working correctly
body: <p>I am exporting matplotlib.pyplot plots to .pgf files to use them in Latex, and therefore I specify the right font family and font sizes beforhand in python. While the legend is formated correctly, the axis labels show around 2pt offset to the font size, and they are not in bold, even though specified . Is it not possible to use RC parameters together with a stylesheet? Here is my code:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import matplotlib.style as pltstyle
  pltstyle.use('ggplot')
  from matplotlib import rc
  from matplotlib import rcParams
  rc('font', **{'family': 'serif', 'serif': ['Latin Modern Roman']})
  rc('text', usetex=True)
  rc('font', size=8)
  rc('font', weight='bold')
  rc('text.latex', preamble=r'\usepackage{amsmath}')
  testx = [1,2]
  testy = [1,2]
  fig, ax1 = plt.subplots()
  ax1.set_xlabel('This Font is too large')
  ax1.set_ylabel('And not bold')
  ax1.plot(testx, testy, color='tab:red', marker='o', label='Right Font Style')
  plt.legend()
  plt.savefig('test.png', bbox_inches='tight')
  </code></pre>
  
  <p>The Resulting Image:
  <a href="https://i.stack.imgur.com/wLyyS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/wLyyS.png" alt="Wrong Font Styles from RC Parameters"></a></p>
  
  <p>Can I force the plot to use the RC parameters?</p>