[Matplotlib-users] problems making grayscale lines

Hi all,

I'm trying to make a plot with several lines, each with a different
grayscale color.  I thought I could do something like 
clrs = ['0.125', '0.25', '0.375', '0.5', '0.625', '0.75', '0.875',
'1.0']
and then either set the color cycle using clrs or just use the
color=clrs[i] argument in a loop that draws the lines.  This kind of
works, but it seems that there's some autoscaling going on.  If I use
values ranging from 0 to 1, the curve with 0 doesn't show up at all
(which I would expect) and the curve with 1 is black.  If I use values
ranging from 0.5 to 1, the curve with 0.5 doesn't show up and the curve
with 1 is gray instead of black.  What gives?  How can I get a set of
curves with gray values ranging from medium gray to black?

As a simple demo if I do:
import matplotlib.pyplot as plt
import numpy as np
import matplotlib.cm as cmap

x = np.linspace(0,1.,num=10)
y1 = 0.5*x
y2 = 0.4*x
fig = plt.figure()
ax = fig.add_subplot(1,1,1)
ax.plot(x,y1,color='0.5')
ax.plot(x,y2,color='1.0')
ax.legend(['y1','y2'])

plt.show()

I get a single visible line that is a sort of medium gray.

Jon
-- 
______________________________________________________________
Jonathan D. Slavin              Harvard-Smithsonian CfA
js...@cf...         60 Garden Street, MS 83
phone: (617) 496-7981           Cambridge, MA 02138-1516
 cell: (781) 363-0035           USA
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