I think certain people who achieve a certain connection with Allah have noor on their face. As to who can see it, the person seeing it probably must be a certain level too! Once I and my brothers were with br. Abdulbadee' of Boston, who is the Ameer of the New England area. He was relating that one day, while sitting in Nizamuddin, there suddenly came a huge amount of noor and tranquility in the markaz. Looking up, he saw that Hadhrat Ji Maulana Inaam ul Hasan and Maulana Umar Palanpuri were returning from their walk. We then asked him aobut noor, and how one sees it, and how it is different from regular noor, etc. , I should have recorded that conversation. I don't remember that much now, but I'll try to ask my brother if he remmebers. I've also heard - I don't know how accurate this is - that there are different colors of noor, and people with a very high status can see the different colors of noor on people. Anyone heard about that before?