transparent (invisible) trace or point on a graph via rgb?



I have a wave that is graphed and each point is colored by setting the wave f(z) to a 3-column color wave. Is there any way to set an rbg to transparent? If I didn't use the rgb wave and instead used a color table, I could set the before or after first color to transparent but that's not ideal for what I am trying to accomplish. I can't set to white (or graph background color) either because there are multiple waves on one graph that shouldn't cover each other.



Try adding a 4-th column to the color wave for the 'alpha' transparency parameter. 'Redimension' is a handy way to do this; then you can control the transparency by specifying what the alpha values are.

Is this an igor 7/8 thing? 6.2 doesn't allow me to select/set a 4-column wave