While all vampires have a fear and loathing of the sun, referring to it as 'The Enemy', not all vampires will die from its light.
Very recently-created vampires can go out in the sun with no abnormal effects: indeed they do not suffer sunburn like mortals, retaining the pallor of death. Somewhat older vampires will not die, but will blaze with a light that is said to be very beautiful. Finally, very old and powerful vampires may be able to go out in the sun, but while they do so lose all their undead powers.
The light emitted by young vampires is said to include colours that are not otherwise found in the world (by which is meant the world wherein lies Teleleli, although there is no overall difference between the light there and in our own world). These extra colours are named by some ulfar and jale. Science tells us that all the colours visible to humans are found in nature. Thus it may be that this light alters its observer, allowing them to perceive infra-red or ultra-violet. Alternatively, it may act directly on the human brain, bypassing actual sight altogether. Perhaps this phenomenon has come connection to the auras said to be perceivable by mystics, or the Third Eye of the Tibetan lamas. The Barsoomians, too, speak of a Ninth and Tenth Ray, which possess various powers, and which their ancestors extracted from normal light by a process now lost.