Many people believe that the higher the colour temperature the brighter the lamp. This is totally wrong. The colour temperature is purely a scale to measure the colour of the light output and is measured on the graph shown as an X and Y coordinate. It is a reference purely for colour and could equally be called White , Green or Blue. The reality is the higher up the scale the headlight lamps are the less bright they become. 4200K lamps are approx 20% brighter (measured in Lumens not degrees K) than the 6000K. If you want lighting performance the 4100K Philips HID lamps are the best on the market with 3500 lumen.

Degrees K = ONLY COLOUR
Lumen= BRIGHTNESS