Curvemeister Forum

I've got a step curve Hue mask - hues up to 84 are mapped to 0% in the mask curve, hues from 85 up are mapped to 100%.  The mask preview looks fine - blacks in the mask view corresponds to 100%, whites to 0%
When I click on the invert button, almost everything goes to white.  When I view the result of curves and masking, I see that almost nothing is masked (so the mask view does accurately represent the effect of the mask).
(I'm in HSB space)

I think what you are seeing is that when the mask is inverted, the curve should be inverted as well, and it is not.  The result is that the curve you created for the un-inverted data is applied to the inverted data, and the result is that everything goes white.  I'll see about fixing this in the next version. 

yes, that makes sense.