Make black less black and render with white lines

[Jaco van der Molen]

Hi all,

How can I define a new color to use in LPub3D.
I have a model with much black and want the black to be less black (more like black rubber or very dark grey) and have the lines around the bricks in white.
I know one can do this in ldconfig? How? I have never used this before.

Thanks!