Hi Kendy,
From the interface, you can follow Drbobshepherd's method. Or you can just uncheck the Enabled check-box in the Color Fill Control group, which is below the color map setting table.
From the script, there seems no script to do it directly. However, you can set each color level to none one by one. For example:
int numColors = layer.cmap.numcolors; // get the number of colors
for(ii = 1; ii <= numColors; ii++)
{
layer.cmap.color$(ii) = 4294967292; // set the iith color to none
}
layer.cmap.colorAbove = 4294967292; // set the color of level above zMax to none
layer.cmap.colorBelow = 4294967292; // set the color of level below zMin to none
Penn