Shade smooth causes dark colours I'm trying to model a chair in blender, and i shaded a part of it smooth. The problem is, the bottom of the object becomes darker, and its not an issue with the lighting position. It also shows in renders.

Here is the chair shaded smooth and not shaded smooth for comparison.
Have you tried enabling auto smooth option with custom angle? By default smooth shading smoothes every edge, but in hard surface models you often need hard edges. AFAIK this angle value sets threshold between hard and soft edges.