This is kind of a pain to find out: from matplotlib.colors import LogNormim = imshow(.... cmap=... , norm=LogNorm(vmin=clevs[0], vmax=clevs[-1])) `` It also works for contours, and can be particularly useful if you only want to display contours at a few levels, but you want the colormap to start at a different point. e.g.: ``contour(xx,levels=[2,3,4,5,6,7,8,9,10],norm=matplotlib.colors.Normalize(vmin=0,vmax=10)) will start at light blue instead of dark blue in the default colormap