A painting is more than its surface.
It is how light moves through it.
About
No painting is finished by the painter alone. Ground, drawing, shadow, colour and glaze wait in the dark, one thin layer over another, until the light of a gallery passes through them and gathers them into a single image.
Lumen-Strata is about two crafts that meet on a museum wall: the painter's, who builds a picture one layer of paint at a time, and the lighting designer's, who decides how those layers are finally seen. Every work comes from the Harvard Art Museums.
01 — Collection
Drawn from the Harvard Art Museums' most-visited paintings, in the order visitors favour them.
No paintings match that search.
02 — Method
One sheet per stage of making, each paired with the instrument conservators use to see it.
No. The sheets are computational analogies. Your browser splits the museum's photograph into seven light filters, each holding the kind of information one stage of painting contributes: a weave, a ground tint, contours, tonal masses, colour, fine detail and a clear varnish. Stacked in a beam, the filters multiply back into the picture. They show what each stage does, not what a particular painter laid down.
03 — Light
i.
Oil paint is partly transparent, so light crosses every layer and returns filtered by all of them.
Light enters a glaze, passes through the colour beneath, bounces off a pale ground and comes back out. That is why Van Eyck's and Titian's glazes seem to glow from within. In the viewer the projector shines through all seven sheets, and what lands on the wall is the painting again.
ii.
Light through a small opening casts an image on the far wall, upside down.
Mozi and Aristotle noted the effect. Ibn al-Haytham (c. 1011–1021) explained it, and Giambattista della Porta (1558) recommended it to painters. Whether Vermeer used one is still debated (Steadman, Vermeer's Camera, 2001; the Hockney–Falco thesis). The viewer's Obscura lens shows the inversion.
iii.
Lift sheets out of the beam and the wall shows only what remains.
Conservators work the same way. They overlay a painting's X-ray, infrared and ultraviolet images on its photograph to see which layer holds which decision: a hidden drawing, a changed pose, a later repaint. The viewer's presets (Infrared view, X-ray view, Under the varnish) recombine the sheets into those ways of seeing.
iv.
Museum light is its own craft: dim, warm and carefully angled.
Conservators and lighting designers balance seeing against fading. Oil paintings are commonly lit at around 150–200 lux, works on paper at about 50. Lamps are often aimed at roughly 30° from vertical so that glare off the varnish falls below the visitor's eye, and warm light (around 3000 K) suits the oil glazes the old masters built up. Every instrument in the Method is another kind of lamp, from X-ray to ultraviolet.
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Separating strata…