Dear Hawkfyr, yesterday night I ungrouped all lights, deleted a lot (too much rendering time) and I checked one of them: infinite light was on, no falloff, intensity 69. I then put them randomly. in the next rendering everything was ok, no more black lines. But I was not happy with it so I changed the camera fov from 60 to 80. I got a better view, but some black lines turned out again.... ....Another question, if I can....this scene has a bottle of nail enamel some of which has fallen on the mirror surface. I created the shape in photopaint black and 50% gray and gave a slight gaussian blur. Applied it to a lattice, lowered, smoothed. But it is not smooth when render. Any tips for this? Maybe this evening I'll upload the image if it doesn't take too much time, so you can see at last what I am talking about. Your help is always highly appreciated and welcome. Thanx again.