errobar color


I'm trying to plot some error-bars in my GUI making use of the WXAgg-backend. My code looks like this:
if parent.error_bar: a.errorbar(x.ichannel,x.intensity,x.intensity_error,ecolor='k')
Now, I can plot the error bars in any arbitrary color, but the my actually black-on-white data are colored blue upon adding error-bars this way. What I want is that everything (data and their errors) is plotted black. Can anybody tell how to achieve this behavior?