Should she glow?

[alatar]

Why the glow?

Science.

Peter Jackson is simply striving to make his films scientifically accurate.

These glowing elves are akin to the Moon, which shines no light of its own but merely reflects that of the Sun. More scientifically, photons emitted by the Sun bounce off (are not absorbed by) of the Moon and enter our eyes and excite electrons in our brains, and then we sit and write poetry.

Anyway, this insight dawned on me while reading FotR (emphasis mine):

Originally Posted by Three is Company

They <Gildor's folk> bore no lights, yet as they walked a shimmer, like the light of the moon above the rim of the hills before it rises, seemed to fall about their feet.

Originally Posted by Fog on the Barrow Downs

As he <Frodo> lay there, thinking and getting hold of himself, he noticed all at once that the darkness was slowly giving way: a pale greenish light was growing round him. It did not at first show him what kind of a place he was in, for the light seemed to be coming out of himself, and from the floor beside him, and had not yet reached the roof or wall.

Originally Posted by A Knife in the Dark

In one hand he <The Witch King> held a long sword, and in the other a knife; both knife and the hand that held it glowed with a pale light.

So clearly the Nazgul emit some time of particle that becomes visible when 'bounced' off of an Elf or and Elf friend. Gildor's troop glow as they (possibly) tramp back up the same path traveled by one of the Nine. The Wights were visited by the Witch King, and his Nazgully presence left a trace that reacted with Elf friend Frodo. We observe this luminescence more intensely on Weathertop.

Morgul weapons retain this radiation, and Elves and Elf friends, by seemingly refusing receipt, repel it, and hence glow. Science.

[More experiments are presently being conducted at CERN].