How does arc look like when bulb is off?
Obviesly the arc disappears when power is turned off. The metal salts will then turn into powder and will fill 1/8 of the bottom of the round glass capsule in the middle of hid bulb. The color of these salts are grey/ green on Philips and Osram 4100K. Philips 6000K has a deep red color, which can be mistaken to be blood. The color of the salt will remain until bulb is turned on again. Below: Philips D2S. The salts have fallen down towards return wire. Salts have turned into solids. Bulb in picture below was burning with return wire down. It was then turned almost upside down. That is why the salts are pointing upwards. Osram Sylvania and blue HID bulbs Osram Sylvania has an HID bulb with higher color temperature as well. They call it D-HC (Discharge-High Color) HID, with 5400K and 2600lm bright and has an integrated starter in the bulb base. It is used in their X1010 Aux low beam kit. Their standard HID capsule has 4100K and is 3200lm bright. 6000K, 7000K, 15000K HID bulb scam Many peo