# Pictorial Space and the Picture Plane

Painting I · Analysis, Project and Presentation · https://tryals.app/learn/painting-i/pictorial-space-and-the-picture-plane

## The Window and the Surface

Leon Battista Alberti published *De pictura* in **1435**. He treated the canvas as an open window. This introduced the **picture plane**, an imaginary surface intercepting light rays.

Filippo Brunelleschi demonstrated the geometry around **1425**. Perspective is a constructed system, not a model of human vision.

### The Geometric Construction

- The **horizon line** matches the viewer's eye height.
- Perpendicular lines converge at a single **vanishing point**.
- The **distance points** set the intended viewing distance.

If distance points sit 45 cm from the centre, the view works only from 45 cm away.

### Calculating Image Size

Let the picture plane sit at distance **D** from the eye. An object of height **h** at distance **d** projects a height of **h x D / d**.

A 1.8 m figure at 6 m, with **D** at 1 m, projects an image of 0.3 m (or 0.30 m).

### Depth Cues

Perspective is only one method to suggest depth:

| Cue | How it operates |
|---|---|
| Overlap | A near object interrupts a further contour |
| Size gradient | Objects render smaller with distance |
| Aerial perspective | Distance lowers contrast and cools colour |
| Texture gradient | Surface patterns compress with distance |
| Height in field | Distant objects sit higher towards the horizon |

### The Flat Surface

Maurice Denis wrote in **1890** that a painting is primarily a flat surface covered with colours. In **1960**, Clement Greenberg argued that flatness defines modern painting.

Every painting balances Alberti's window against Denis's surface.

> **Common pitfall:** Perspective is a geometric projection from one static point. It lacks binocular vision and eye movement. It is a drawing system, not natural sight.

## Practice questions

8 of this lesson's 14 practice questions, with answers. The full set is in the app.

### 1. Complete the account of pictorial space.

**Answer:** Alberti described the picture as an open **window** through which the subject is seen, in De pictura of 1435. The line on which perpendiculars converge sits at the height of the viewer's **eye**. The cue by which distance lowers contrast and chroma and cools the hue is called **aerial** perspective. Maurice Denis insisted in 1890 that a picture is essentially a **flat** surface covered with colours assembled in a certain order.

**Why:** The first and last blanks are five centuries apart and contradict each other. Alberti asks the viewer to look through the surface; Denis asks them to look at it. Every painting since has had to decide which of the two it is doing, and most interesting ones do both at once.

Page: https://tryals.app/practice/painting-i/pictorial-space-and-the-picture-plane/complete-the-account-of-pictorial-space

### 2. A painter places a standing figure's feet exactly on the horizon line, and a tutor says the figure now reads as standing infinitely far away. Why does the construction force that reading?

A. The horizon marks viewer eye level, so placing feet there implies the figure floats in mid-air
B. Orthogonals converge at the feet, eliminating foreshortening and flattening the figure fully
C. The horizon projects the ground at infinity, so feet placed there denote an infinite distance
D. Aerial perspective removes all depth scaling and spatial cues for forms placed at the horizon

**Answer:** C. The horizon projects the ground at infinity, so feet placed there denote an infinite distance

**Why:** The ground plane projects higher and higher as distance increases, and the horizon is the limit it approaches and never reaches. Feet placed on it therefore correspond to no finite point on the ground at all. The figure has not been put far away; it has been put nowhere the ground plane can supply.

Page: https://tryals.app/practice/painting-i/pictorial-space-and-the-picture-plane/a-painter-places-a-standing-figures-feet-exactly-on-the-horizon

### 3. A one-point construction has its distance points 45 centimetres to either side of the centric point. From how far away, in centimetres, must the picture be viewed for the construction to be correct?

**Answer:** 45 (within ±1)

**Why:** **45 centimetres.** The construction is right from one place only, and that place is fixed the moment the distance points are chosen. Choose them close together and you have built a picture for a viewer with their nose against it, which is exactly how a painting acquires a distortion nobody can correct later.

Page: https://tryals.app/practice/painting-i/pictorial-space-and-the-picture-plane/a-one-point-construction-has-its-distance-points-45-centimetres-to

### 4. Brunelleschi formulated linear perspective as a geometric projection rather than a replication of natural sight. What follows from this distinction for a painter organising pictorial space?

A. The picture plane ceases to operate as an interceptor of light rays
B. Natural binocular vision must be reconciled via multiple horizons
C. The construction presumes an immobile, monocular station point
D. Optical depth cues are replaced entirely by mathematical convergence

**Answer:** C. The construction presumes an immobile, monocular station point

**Why:** Conflating geometric projection with natural sight overlooks that perspective mathematically freezes sight to a single fixed eye. Depth cues remain operative alongside geometry, and the picture plane still intercepts rays; geometry formalises rather than eliminates planar projection.

Page: https://tryals.app/practice/painting-i/pictorial-space-and-the-picture-plane/brunelleschi-formulated-linear-perspective-as-a-geometric-projection

### 5. Which of these are depth cues that work without any perspective construction?

A. A regular texture compressing as the surface recedes
B. One object interrupting the contour of another
C. Distant objects rendered with lower contrast and cooler hue
D. Lines perpendicular to the picture plane converging on a point

**Answer:** A. A regular texture compressing as the surface recedes; B. One object interrupting the contour of another; C. Distant objects rendered with lower contrast and cooler hue

**Why:** The fourth is the construction rather than a cue independent of it. The others need no geometry at all, which is why painting outside the European perspective tradition builds convincing depth without a vanishing point anywhere, and why landscape survived the abandonment of perspective while architectural painting did not.

Page: https://tryals.app/practice/painting-i/pictorial-space-and-the-picture-plane/which-of-these-are-depth-cues-that-work-without-any-perspective

### 6. Arrange the steps of setting up a one-point perspective construction in order.

**Answer:**

1. Decide the viewer's eye height and draw the horizon line there
2. Choose the centric point on that horizon
3. Choose the distance points, which fixes the viewing distance
4. Draw the orthogonals from the picture's base to the centric point
5. Use the distance points to space the transversals correctly in depth

**Why:** The third step is where the viewer gets built into the picture, and it is the one that is usually skipped. Choosing the distance points is choosing where a person will stand, and everything about how the finished painting behaves in a room is decided by that choice rather than by anything painted afterwards.

Page: https://tryals.app/practice/painting-i/pictorial-space-and-the-picture-plane/arrange-the-steps-of-setting-up-a-one-point-perspective-construction

### 7. A doorway 2 metres tall stands 12 metres from the eye, with the picture plane 1.5 metres away. How tall is its image on the plane, in centimetres?

**Answer:** 25 (within ±3)

**Why:** **25 centimetres.** Two metres multiplied by 1.5 and divided by 12 gives 0.25 metres. Moving the picture plane out from the eye scales every image up in proportion, which is exactly why the same construction drawn on a larger sheet at a greater distance is the same picture, only bigger.

Page: https://tryals.app/practice/painting-i/pictorial-space-and-the-picture-plane/a-doorway-2-metres-tall-stands-12-metres-from-the-eye-with-the

### 8. Sort each device by how it produces depth.

**Answer:**

- Geometric construction: Converging orthogonals, Spaced transversals
- Atmospheric and tonal: Paler, cooler hills, Haze softening darks
- Neither: it works by occlusion or convention: Overlapping contours, Higher distant figures

**Why:** The third column is the one that travels. Occlusion and height in the field are read by viewers with no training in the European construction at all, which is why paintings from traditions that never adopted perspective are still spatially legible, and why the construction is best understood as one option rather than as the default.

Page: https://tryals.app/practice/painting-i/pictorial-space-and-the-picture-plane/sort-each-device-by-how-it-produces-depth