Using Molekel 5.2.0.5 it is not possible to change/choose the color of the surfaces (both signs) when visualizing orbitals from a calculations. The colors of + and - surfaces cannot be changed from the blue and greenish, which make them very difficult to distinguish especially when the orbital figures is printed in black and white (against a white background, as in a publication). Is there a way (e.g. editing a ascii file as one does for changing element colors) to choose the surface colors in the visualization of orbitals? Is it possible to do that in the 5.3 version? Best Regards and Thank you for the hard work, Matteo