ENOGU

← All the investigations

Research

What the oil masters delivered, and how modern painters built on it

Question: what did the great oil painters actually achieve with the physical material, and what does each achievement demand of the app? Every entry ends with a concrete implication. This isn't a history lesson; it's a requirements list with a 600-year test suite.

The masters

Jan van Eyck (1430s) — optical depth. Thin, translucent oil glazes over a smooth, brilliant white chalk ground. Light travels through the colour, reflects off the ground and comes back out, so the colour glows from inside. This is what oil made possible that egg tempera couldn't. → Glazing is a first-class operation. The ground matters: offer a white gesso and toned grounds. KM layer-over-substrate gives this for free.

Titian (late works, 1560s–70s) — the visible touch, and fingers. He laid in a mass of colour as a foundation, then built on it over months. Palma Giovane, his pupil, reported that he finished "more with his fingers than his brushes": blending transitions, pressing a dark accent in with a finger, reviving a surface with a spot of red "like a drop of blood." → The finger is a historically legitimate painting tool, which justifies iPhone-first. A finger-smudge tool that moves and blends paint without adding any is core.

Rembrandt (1650s) — relief as light. He built highlights with thick lead white and painted shadows thin and dark, so the paint is physically highest exactly where the depicted light is brightest. In a gallery the raised paint catches real light, extending the painting's tonal range beyond what pigment alone can do — an effect "that cannot be reproduced in photographs." Synchrotron studies (ESRF, 2019) found plumbonacrite in his impasto: he likely cooked lead oxide into the oil to make a stiff paste that holds its shape. → Height and light must interact in the renderer, so that thick lights read brighter under a moving light. Paint needs body: a stiff, fat white that holds a peak.

Velázquez (1650s) — economy. Loose, single, loaded strokes that look like nothing up close and resolve into lace, silk or light at a distance. → Zooming out is the painter's step back. The canvas has to render honestly at both distances, and a single stroke has to carry enough information to resolve.

Constable & Turner (1810s–40s) — outdoors, and the scraped surface. Constable painted small oil sketches outdoors and flecked light on in broken white ("Constable's snow"). Turner scraped, scumbled thin veils over thick paint, and worked with knife, thumb and fingernail. → The pocket study is historically the natural format for a phone. Scrape-back and scumbling (dry, broken paint dragged over tooth) are required tools.

Courbet (1850s–60s) — the palette knife as primary tool. Not a scraper: the knife as the thing that lays paint, giving flat, glossy planes with sharp ridged edges, especially in rock and snow. → The knife is a first-class tool with its own physics: it levels paint to the blade, leaves flat glossy plateaus, and throws ridges at the edges.

The Impressionists and the tube (1841 →) — portability, alla prima, optical mixing. Rand's 1841 collapsible tube let paint travel. Painters laid short strokes of relatively unmixed colour side by side and let the eye mix them. → Don't over-blend, because broken colour is a technique. Portability changes what gets painted, and the phone is the next portable format.

Van Gogh (1886–90) — directional impasto: the stroke is the drawing. Paint laid thick, often straight from the tube, in strokes whose direction describes the form: the swirl of the sky, the rake of the wheat. The Van Gogh Museum and Fujifilm's Relievo 3D-scan every ridge and print full-scale relief replicas, an institutional statement that the relief is the work. → Store the stroke direction per texel and render its anisotropic highlight. Without it Van Gogh is literally unrenderable. The relief print is a real product precedent.

Sargent, Sorolla, Zorn (1880s–1920s) — bravura alla prima. Wet-into-wet in a single session, big loaded brushes, few decisive strokes. Zorn's four-colour palette (ochre, vermilion, ivory black, white) goes back to Apelles, according to Pliny. → Wet-into-wet has to feel great, because it's the main use case on a phone. Ship the Zorn palette as the default.**

The moderns — how they built on it

Willem de Kooning (1940s–70s) — "Flesh was the reason oil paint was invented." Wet-into-wet slurs, dragging and scraping, paint kept workable for long periods. → Long-wet mode: the canvas can stay open for days.

Lucian Freud (1970s–2011) — pigment with a body. From the mid-1970s he reserved Cremnitz white, a heavy, granular, stiff lead white, for painting flesh, because its texture was like flesh. → Pigments differ in rheology, not just colour. Each pigment gets its own stiffness and grain: Cremnitz ≠ titanium white. No app does this.

Frank Auerbach (1950s–2024) — the painting as archaeology. Paint scraped off entirely at the end of a day and rebuilt the next, for months: "Every time I scrape it all off I know a bit more." The final surface is a thick crust made by all the attempts beneath it. → Scraping down is a real action, not undo. The drying clock and a painting's history are materials. A time-lapse of the scraped layers is a strong share format.

Gerhard Richter (1986 →) — the squeegee. Wet layers dragged across the whole surface with a long Perspex blade, burying some colours and revealing others. "With a brush you have control… with the squeegee you lose control." → The squeegee is a wide knife, so it's the same physics. It's also the most dramatic demonstration of a height- and wetness-aware simulation, because it's pure transport.

Jenny Saville, Cecily Brown (1990s →) — paint as sculpture, the canvas as a record. Saville uses thick, wet-into-wet paint "in a sculptural way," and quotes de Kooning on flesh. Brown calls the canvas "a record of [her] movements." → The document keeps the gesture: stroke direction, speed, order. Replay is a feature.

The atelier and plein-air revival (today) — alla prima, limited palettes, the Zorn palette as standard in portrait workshops, and small panels painted outdoors. → This community is probably the beachhead (see The market.5). They already think in the app's vocabulary.

Eight requirements this history hands us

  1. Two kinds of depth: relief (Rembrandt) and optical (van Eyck). Build both.
  2. The hand is recorded: stroke direction (Van Gogh), gesture (Brown). Store tangent and order.
  3. More tools than the brush: finger (Titian), knife (Courbet), squeegee (Richter), scraper (Auerbach, Turner).
  4. Pigments have bodies: stiffness and grain per pigment (Freud, Rembrandt).
  5. A limited palette by default: Zorn, a lineage of about 2,400 years.
  6. Time is a material: long-wet (de Kooning), scrape and rebuild (Auerbach).
  7. Portability changes what gets painted: the tube led to plein air; the phone leads to the pocket study.
  8. The object can't be photographed (Rembrandt, RTI, Relievo), so the share must be relightable.

Onboarding idea: the first lessons are the masters. A Rembrandt highlight (thick white on a thin dark), a Van Gogh wheat stroke (direction), a Courbet knife plane, and a Zorn portrait with four colours. Each one teaches a piece of the physics by doing it.

Sources

Written 2026-09-24. Kept as it was written; the app may have moved on since.