Synaesthesia.

Every mover is a measurement; the instrument is declared. The picture's spectrum is the bed: its slope is the drone's timbre, and the column under the head sounds on a ladder spaced by the ear. The picture is one resonant body: its root is its tonic (the sun when there is one, else the dominant colour's light brought down by octaves, else A) and its ladder is the pentatonic on that root (the harmonic series' own sevenths were heard as out of tune), so every held voice, the drone and the column belong to one root; the drone is two singers eight cents apart, ten partials deep. Above the bed, the readings each have a declared vocabulary of what counts as a thing, scored on a corpus of photographs; the found ones play, and any can be switched on. Darkness deepens the ground: the drone gains the octave below and loses its upper partials as the column darkens. Lines and arches are held tones that step along the ladder with their own height as the head crosses them, so a diagonal is a run and an arch a rise and fall. Colour is the light's own frequency forty octaves down, red near 420 Hz and violet near 650 Hz, each hue drawn to the nearest step of the picture's ladder so the colours sit in tune with the ground, up to five at once entering one after another in the light's order, red first (Riley), loud by chroma, the hue its timbre (a warm colour rich in harmonics, a cool one nearly pure), each colour sung as a pad of two of its tones five cents apart, a dark colour carrying its octave below, a colour low in the picture an octave down. A rainbow is the spectrum in order down a column: it plays as a chord of its own light, strummed in its own order. Dashes are birds, each a phrase of syllables after the syrinx: a nearly pure tone whose pitch walks a smooth path, the loudness riding the sweep; the species is the dash's size (the thinner the dash, the smaller the bird and the higher its voice), the phrase its darkness profile (every lobe that stands out a syllable, a ribbed dash a trill, a smooth one a single call), each syllable an arc or, where the profile mostly rises or falls, a sweep that way, the stroke's slope tilting it, the sweep as wide as the dash is deep (up to an octave), two birds at a time at most; a mass of dashes, more than three a second under the head, is a cloud of soft grains at their own heights (Xenakis); cracks are strings of their own length, the main fissures sustained through an "oh" of two formants and bending along their path, the fine ones plucked as glass, the crackle as grains; in a busy picture only the four strongest lines sound (Ikeda); vertical lines are strings of their own height, longer lower, struck as the head passes; the skyline is a voice, two oscillators four cents apart sung through an "oh", twice the root at the foot of the frame rising an octave and a tone to its top, each note swelling in and settling, with a bell voice below it on the root's triad (Pärt's rule); the sun is the tonic; pigment sings a vowel. Where the picture repeats along the crossing (a true second peak in the autocorrelation of its texture or its light along x, prominent, two beats at least), the crossing has a pulse: a thump of the root and its octave marks each beat; where nothing repeats, there is no beat. The voices were chosen by measured roughness, shrillness and pitch movement, then their settings by a search over a corpus of sixty photographs judged by Audiobox Aesthetics, a model of listeners, with the ear's verdicts held fixed. One room holds them, declared as scenery: six seconds, a cathedral.