I’m trying to adjust the font weight in matplotlib, of a non-default font. However, for some reason the font weight doesn’t change when I use Avenir (.ttc font), Geneva (.ttf font), etc.

I’m running Mac OsX 14.5, Python 3.10, matplotlib 3.7.2.

I tested the default behavior and two other fonts:

fig, ax = plt.subplots(1,2)
ax[0].text(0.5,0.5, "Bla", weight = "normal", fontsize = 20)
ax[1].text(0.5,0.5, "Bla", weight = "heavy", fontsize = 20)

Default font:

Now, using non-default fonts:

font = {'family' : 'Avenir',
    'weight' : 'normal',
    'size'   : 15}
plt.rc('font', **font) 

fig, ax = plt.subplots(1,2)
ax[0].text(0.5,0.5, "Bla", weight = "normal", fontsize = 20)
ax[1].text(0.5,0.5, "Bla", weight = "heavy", fontsize = 20)

Avenir:

font = {'family' : 'Geneva',
    'weight' : 'normal',
    'size'   : 15}
plt.rc('font', **font)

fig, ax = plt.subplots(1,2)
ax[0].text(0.5,0.5, "Bla", weight = "normal", fontsize = 20)
ax[1].text(0.5,0.5, "Bla", weight = "heavy", fontsize = 20)

Geneva:

I’m wondering if anybody knows why I’m getting this strange behavior and what I could do to fix it?