On Thursday, May 24, 2012, Jerzy Karczmarczuk wrote:
Gurus,

Windows XP, matplotlib 1.1.0. Backend Tk, but the same elsewhere.

Programme:

import matplotlib as mpl
import matplotlib.pyplot as plt
mpl.rcParams['lines.linewidth'] = 2
mpl.rcParams['lines.color'] = 'r'

x=range(800)
y=[t for t in x]
plt.plot(x,y)
plt.show()

# ==============================
Linewidth OK, equal to 2, but the line is still blue. Changing "r" to
red, or to #ff0000, or (1,0,0) doesn't change anything, still blue.
Changing directly the matplotlibrc file (default) - the same. Leaving in
peace the defaults, constructing another rc in the working dir - the
same. The dictionary rcParams contains the correct value
'lines.color': 'r'
(Anyway, rcsetup.py validation doesn't protest. But then, the modified
colour is ignored).

Somebody could confirm that?

The best.

Jerzy Karczmarczuk
Caen, France

Plot() doesn't use lines.color.  I don't remember the exact name, but it uses an rcparam for color cycling.  Just change make the list of colors be just 'r'.

Ben Root