Window-glass does its job when we don’t notice it. And when we do notice it, it is really the alteration in our vision that we are noticing. The smudge or cloud that obscures, the color that transforms.
Light stains the air.
Religious architects understood the figurative power of glass, its ability to alter space through its own translucence.
Its virtue is translucence, its permeability to light. But never perfectly: light alters glass, as glass alters light.
Some of my favorite writers viewed this quality, in particular, as fascinating. For Virginia Woolf, translucence became a signifier of consciousness itself, coloring and colored by the play of the world through our personalities.
FROM THE OVAL-SHAPED flower-bed there rose perhaps a hundred stalks spreading into heart-shaped or tongue-shaped leaves half way up and unfurling at the tip red or blue or yellow petals marked with spots of colour raised upon the surface…The petals were voluminous enough to be stirred by the summer breeze, and when they moved, the red, blue and yellow lights passed one over the other, staining an inch of the brown earth beneath with a spot of the most intricate colour. The light fell either upon the smooth, grey back of a pebble, or, the shell of a snail with its brown, circular veins, or falling into a raindrop, it expanded with such intensity of red, blue and yellow the thin walls of water that one expected them to burst and disappear....
-- from "Kew Gardens"
Or there is this, Walter Pater writing of diaphaneity as something approaching an ethical value, or perhaps as an explanation of how humans convey – are conveyed by – history.
There is another type of character, which is not broad and general, rare, precious above all to the artist, a character which seems to have been the supreme moral charm in the Beatrice of the Commedia. It does not take the eye by breadth of colour; rather it is that fine edge of light, where the elements of our moral nature refine themselves to the burning point. It crosses rather than follows the main current of the world’s life.
-- from "Diaphaneite"
Though technically glass is something other than (or in between) a solid and a liquid, it’s apparent viscosity can make it seem like a slow liquid. Millennia-long currents flow in glass, forming tides and waves
That make vision ancient.
It frames what we see through it, stills and removes the world from us, so that we see the world for what it is: Art.