Vertical architectural interior photograph of the drained tiled basin of a swimming hall that has been closed for years. 9:16 vertical, photorealistic, single frame, editorial print quality, available daylight only. No lamp is switched on anywhere in this building.

THE ROOM. A long indoor swimming hall from the nineteen seventies, abandoned but still weathertight: the roof does not leak, no plants grow inside, nothing has collapsed. The camera stands on the tiled deck at the shallow end and looks lengthwise down the whole empty basin towards the far end wall. The basin is completely drained and completely dry. Its vertical side walls and its floor are clad in small turquoise ceramic tiles, and the floor slopes gently away from the camera towards the deep end. The left hand side wall of the basin stands about one and a half metres high and runs away from the camera into the depth of the picture, and it takes up the whole left side of the frame.

THE TILE GRID, WHICH IS WHAT THIS PICTURE HAS TO PROVE. Every tile is a small square roughly ten centimetres across with a narrow pale grout line about four millimetres wide between them. They form one single true grid over the entire basin: rows and columns straight and unbroken, the columns running away from the camera and converging on ONE vanishing point near the centre of the frame, the rows staying strictly horizontal across the picture. Because the surface recedes, the grout lines must grow visibly narrower and the rows visibly closer together towards the far end, and they must stay evenly and correctly spaced everywhere, including in the corners of the frame and at the very edges. The grid folds correctly over the geometry it covers: on the vertical side wall the rows run horizontally and the columns run vertically, on the floor the same tiles lie flat and recede, and the grid bends cleanly around the rounded cove where the wall meets the floor. Exactly ONE black tile lane line runs down the middle of the basin floor and there is no second one: a single continuous dark stripe, one tile wide, straight, dead in line with the perspective, running from the bottom of the frame to its vanishing point, with no cross bar, no end marking, no branch and no parallel stripe anywhere on the floor. The turquoise is not uniform: individual tiles sit a shade lighter or darker than their neighbours in a random, non repeating scatter, a few are faintly crazed, some have lost their glaze to a chalky matte bloom. The whole surface is dulled by a fine even film of grey dust. Never a repeating identical texture tile, never moire, never a pattern that drifts, warps, melts or changes scale towards the frame edges.

THE ONE PLACE THIS ROOM IS BROKEN, AND EVERYTHING FOLLOWS FROM IT. The damage is on the VERTICAL LEFT HAND SIDE WALL of the basin, well above the floor, roughly at the middle of that wall's height — it is NOT on the floor and NOT at the foot of the wall. There, a single field of about twenty five tiles has broken out of the wall, spanning roughly a fifth of the width of the frame. It is one connected wound with a ragged irregular outline, not a neat rectangle. It exposes the grey cement screed underneath and, in it, the dried tile adhesive still carrying the parallel comb ridges of the trowel and the square imprints of the tiles that used to sit there. Along the edge of the wound the surviving wall tiles are cracked and lifted; two or three stand slightly proud of the wall, one is tipped and about to fall out. On the basin floor directly beneath the wound lie five or six broken tile shards and a small heap of grey grit, exactly where they would have landed. NOTHING is broken anywhere else in the room. From the lowest point of the wound, and only from there, a water stain runs DOWN the face of the wall as a narrow dark ochre streak, reaches the floor at the foot of the wall, and there spreads out across the basin floor: rust brown, fanning wider as it follows the fall of the floor away from the camera towards the deep end, crossing the black lane line, soaking into the grout more darkly than into the glaze, edged by two or three concentric drying rims where the puddle stood and shrank at different times. It is one continuous flow with one source, obeying gravity on the wall and the slope on the floor. It does not begin in mid air, it is not scattered around the room in decorative patches, and there is no second stain anywhere. A faint chalky white calcium line runs level all the way around the basin at the old water level.

WHAT ELSE IS IN THE BASIN, AND NOTHING MORE. On the near coping at the very bottom edge of the frame, two stainless steel ladder sockets sit flush in the tile, their rails long since removed, each a dark round hole with a rust coloured tear running down the tile below it. Nothing else at all: no ladder, no handrail, no steel rails or bars standing anywhere in the picture, no water, no puddle, no rubbish, no leaves, no furniture, no lane ropes, no starting blocks, no diving board, no signs, no boards, no graffiti, no debris field, no scattered props.

THE FAR END WALL IS PLAIN. The end wall of the basin, and the hall wall above it, are completely plain turquoise tile: no black target crosses, no aiming marks, no T shapes, no dark markings of any kind, no fittings, no pipes, no grilles, no brackets, no doors, no openings, no hatches. It is one large empty tiled surface and nothing is on it.

THE LIGHT, AND THE PICTURE LIVES ON IT. There is exactly one source: a long row of high clerestory windows running along the upper left wall of the hall, seen from below at a steep angle so that it compresses into a narrow band close to the top of the frame. The panes are blind — grey with decades of lime scale and dust — so the light is soft and colourless, overcast midday light around 6000 Kelvin, with no sun disc and no hard beam. This light does not fill the room evenly. It passes over the wall beneath the windows, which therefore stays dim, and lands steeply from the upper left as ONE bright elongated pool on the middle and far part of the basin floor, brightest at the left where it strikes the broken wall and the shards, and falling away steadily to the right and towards the camera. The near third of the basin, closest to the camera at the bottom of the frame, sinks into deep shadow. The tonal range is wide and clearly separated: bright chalky light on the damaged wall and the floor around it, deep shadow in the near foreground and along the right hand side, and no part of the picture is flat, milky or evenly lit. Every shadow in the picture — the lifted tile edges, the shards on the floor, the ladder sockets, the lip of the wound — falls in the same direction, down and to the right, soft edged, with no second shadow anywhere. Fine dust hangs in the air and slightly veils the far end of the hall, greying it and lowering its contrast, but there are no sharp visible light shafts, no god rays and no volumetric beams.

COMPOSITION AND SAFE AREA, IN EXACT PROPORTIONS OF THE PICTURE HEIGHT. Measure from the TOP edge downwards. The top eight percent is dark roof space: dim painted steel trusses and boarding, almost black, no detail worth reading. The band of clerestory windows runs across the upper left of the frame between about eight and seventeen percent, a soft pale glowing stripe with no visible frame detail and nothing sharp in it. From seventeen percent down to thirty eight percent there is NOTHING but the plain shadowed upper wall of the hall: one large empty dim tiled surface, evenly toned, no object, nothing bright, nothing sharp, no edge crossing it, no marking, nothing important there at all — this band is deliberately quiet and dark. The far end wall of the basin and the top edge of the basin meet the eye at about forty two percent. The broken tile field on the side wall sits at about fifty eight percent of the height and clearly LEFT of centre, roughly twenty five percent across the width, and it is the sharpest and most detailed thing in the frame. The shards lie on the floor just beneath it around sixty eight percent. The water stain runs down the wall there and then out across the basin floor, reaching its widest at about seventy six percent of the height and just right of centre. The black lane line runs up the middle of the floor from the bottom edge to its vanishing point at about forty six percent. The near coping and the two ladder sockets cross the bottom of the frame between ninety two and one hundred percent. Everything that matters lies between forty two and eighty five percent of the picture height and inside the middle two thirds of the frame width, so the picture reads exactly the same cropped to 9:16 and cropped to 4:5. Works in both 9:16 and 4:5 crops.

OPTICS. 20mm wide angle lens at f/11, four seconds, ISO 100, camera on a tripod on the pool deck at head height, aimed straight down the length of the basin and held exactly level so that every vertical edge in the room stays truly vertical and no lines converge upward or downward. Deep depth of field: the broken field, the shards and the stain are critically sharp down to the grain of the exposed screed, the far end of the hall softens only through the dust in the air, not through defocus. Natural corner falloff, mild vignetting, fine honest film grain in the mid tones and shadows, no lens distortion, no fisheye bulge.

RENDERING. Real fired ceramic glaze with real chips and real crazing, real dry cement, real dust, real rust. Restrained palette: dulled turquoise, chalky grey white, ochre rust brown and clean deep black — no fourth colour anywhere, no green, no blue cast, no warm amber grade. Deep clean blacks with no lifted grey haze, high micro contrast, muted and slightly desaturated but never washed out, never pale, never milky, editorial print quality, no HDR flattening, no glow, no bloom.

No text, no letters, no numbers, no digits, no lane numbers, no depth markings, no signs, no boards, no plaques, no stickers, no labels, no graffiti, no typography anywhere in the frame. No logos, no brand marks, no watermark, no signature. No people, no hands, no reflections of people, no animals, no birds. No water, no puddle, no wet surface, no mirror reflection, no ripples. No second light source, no lamp, no bulb, no floodlight, no light on anywhere, no visible sun, no sunbeam, no light shaft, no god rays, no volumetric fog beams. No conflicting shadows, no shadow falling to the left, no double shadows, no shadowless flat lighting, no evenly lit interior. No repeated identical tile texture, no moire, no grid drifting, bending, melting or warping at the frame edges, no tiles that lose their perspective, no smeared or dissolving grout lines, no impossible corner. No damage on the floor, no hole in the floor, no second broken area, no decorative decay, no evenly scattered rubble, no rubble field, no collapsed ceiling, no hole in the roof, no ivy, no plants, no moss, no mould blooms, no peeling paint everywhere, no random cracks all over the room. No colourful mosaic, no pattern of fish, waves, dolphins or ornament in the tiles. No wide angle bulge, no tilted horizon, no dutch angle, no drone view, no fisheye, no HDR tone mapping, no orange and teal grading, no cinematic colour grade, no plastic sheen, no CGI look, no video game render, no architectural visualisation look, no painterly or illustrated style, no letterbox bars. Nothing at all in the top thirty eight percent of the frame except dark roof, the soft window band and empty shadowed wall.