Yes, when you "dim" an incandescent lamp the filament temperature decreases which results in a warmer or redder illumination.
Generally, if you want accurate color rendition, you want to use a light source similar in temperature to daylight- about 5500k. Halogen (undimmed) is slightly warmer, around 3400k but better than regular incandescent. Metal halide comes close, so close that most motion picture sets are illuminated with them. Also very close are some flourescents. Check out the flourescent lamp product catalogs for those that have a color temperature of 5500k.