colormaps

Setting a ScalarMap with Display.RGB seems to give you a nice
grey-scale image with alot of detail.  I have been playing with
producing the image with a colormap and notice in the examples
that one seems to have to create a LabeledRGBWidget in order
to get a colormap.  Doing this gives me a default map, but I have
lost my detail.  I have been playing with the min,max values sent
into the constructor for LabeledRGBWidget, and got a little bit
more detail, but not near the same as grey-scale.

How can I get more control over the colormap?

And how do you use the widget to control color??  That seems to only
alter
the red curve, and by dragging a point, instead of smoothing out the
curve.

Thanks,
KathyLee Simunich
Argonne National Lab