The early use of lustre was full of light--literal and figurative.
Splendor Solis by Solomon Trismosin in 1582 suggests reflected light on the surface of metals:
His definition of it is that it gives lustre to metals, and colour and
fragrance to flowers.
On page 400 of Certaine articles or forcible reasons in 1600, Thomas Wright and Etienne Binet suggest refracted light from a diamond:
O goodly miracle to behold her so long time a Virgin in the midst of
the Court , as a Diamond among flames and not be melted, nor to haue
the lustre of its sparkling lessened'
On Page 169 of Du Bartas His Deuine Weekes and Workes in 1613, Guillaume de Salluste Du Bartas used lustre to describe the light of the sun reflecting off of the moon:
The Sun there shifting in the Zodiack
His shining Houses, neuer did forsake
His pointed Path: there, in a Month, his Sister
Fulfill'd her course and changing oft her lustre
And form of Face (now larger, lesser soon)
Follow'd the Changes of the other Moon.
On page 7 of The Lady's Privilege: A Comedy in 1640, Henry Glapthorne used lustre for the shining light of the sun:
... subjects ought to offer,
With the sincere devotion that our priests
Do prayers to heaven, their hands as sacrifices
To their deserving princes, whose sole favours
Do, as the quick'ning lustre of the sun,
Cherish inferior spirits.
In 1613, Thomas Heywood used lustre for the metaphoric light of the face in A Marriage Triumph, on the Nuptials of the Prince:
Such lustre in Adonis cheeke did move,
When he was haunted by the queene of love:
So looked Hypolitus when, clad in greene,
He was oft courted by th' Athenian queene.
It was quite common to use lustre for the glory of God in mankind, as on page 71 of Several sermons and discourses of William Dell:
They have a more excellent lustre then other men. One thing that
appertaines to the excellency of precious stones, is the lustre of
them. Now this lustre in the faithfull, is the glory of God upon them:
Wan suggests the colorless grey of dusk. The reflective luster of everything on earth diminishes, as the lustre of the sun decreases at sunset.