The Art and Science of Depiction -- Frédo Durand and Julie Dorsey

Extended syllabus

Presentation of the class, discussion of the motivations and backgounds of the students. Brainstorming about the issues that should be addressed.


There is no passive recording
We will show that photography and cinema are hardly passive recordings. Make-up, cinema lighting, film processing, editing. We will also see that realism is not always what we need.


What is an image?
Introduces the global context of pictures, and the elements of the chain that lead from reality to a picture. Discusses the double nature of images, as 2D objects and depiction of a 3D reality.


Human vision
Low level human vision, photoreceptors, visual pathways and specialized analysers.


Human and computer Vision
Ecological approach to vision (human vision is "optimized" to acquire information in our environment), invariants and constancy (an object must be perceived "the same" seen under different lighting, different viewpoints).
Computer vision and vision as information processing, perceptual level of representation and depiction style


Physics of colors, wavelength, spectrum, decomposition of white light, reflectance of objects and visible color. Human color vision, color spaces. Color effects, color appearance models. Cultural aspects


Limitations and compensations
The most classical limitation of 2D media is their inability to provide stereovision and depth. We will study this limitation as well as others, and show which pictorial techniques have been developed by artists to compensate (or accentuate!) these limitations.
The picture is flat, the viewpoint is unique, the picture is finite.
The image is static, the contrast is limited, the color gamut is limited.


Representation systems
Introduces the classification of the technical issues involved in the depiction of reality. the drawing system, the denotation system and the tone system.


Drawing and perspective
Linear perspective and orthographic projections are the most known drawing systems, but we will also discuss projections used by cubist painters, Byzantine divergent perspective, topological projection, etc.


Distortions of linear perspective, alternative perspective systems. Perspective issues as a set of constraints. We will show that the projection of a 3D scene onto a 2D picture can be an over-constrained problem, hence the issues related to perspective, the numerous possible solutions and the richness of visual arts.


Denotation systems
Studies the primitives used in pictures (regions, lines, points), and the marks used to represent them (brush, strokes, etc.).


Line drawing
Studies line drawings, which lines are depicted (silhouette, discontinuities, etc), evokes some underlying mathematical theories and perceptual aspects.


Optical system: reality
Short introduction to light propagation, shadow, inter-reflections, materials aspects, atmospheric perspective. Perceptual aspect of shadows, why they are rarely represented.


Tone system: picture
How are the colors and tones of the picture affected? Fidelity to the colors of reality is one option, but image composition, ambiance, symbolisms, etc. also play a crucial role.


We will finish by a discussion of the elusive notion of style and how the notions introduced in the class can be used to study and describe style.