Slope Shader gives inverse relief

NEV

Using Slope Shader in a LiDAR display. when viewed with north to the top of the screen gives (to my eye) an inverse relief model (streams on ridge crests - ponds as small plateau!). When I Rotate Map view 180 I get a sensible (to me) relief view. Is there a way to compensate without having to rotate the view? I tried swapping the colours on the Max and Min slope options but no decent result. Am I correct that Light Direction Azimuth and Altitude are not functional in Slope Shader?