VIS-210 · Lesson 11 of 12 · 29 min

Color, digital and the networked image

For most of its first century, serious photography was black and white. Color existed in commercial and amateur work but was widely dismissed by art photographers as vulgar or unreliable. Its acceptance as an artistic medium in the 1970s was one of the major shifts in photographic history. Soon after came another: the transition from film to digital capture, and then the networked, computational and AI-assisted images of the smartphone era. This lesson follows these changes and asks how they have affected the theories of the previous lessons, especially the belief in the photograph as an index of reality.

Early color processes

Photographers wanted color from the beginning. Some daguerreotypes and cartes de visite were hand-colored with pigments. In 1861 the physicist James Clerk Maxwell demonstrated additive color by photographing a tartan ribbon three times through red, green and blue filters and projecting the results together. The first commercially successful color process was the Autochrome, introduced by the Lumière brothers in France in 1907. Autochrome plates used microscopic grains of potato starch dyed red-orange, green and violet as tiny filters over a black-and-white emulsion. The result was a unique color transparency with a soft, pointillist quality, beautiful but slow and expensive.

Multi-layer color films transformed color photography. Kodachrome, introduced by Kodak in 1935 and developed by the musicians and amateur scientists Leopold Godowsky Jr. and Leopold Mannes, used three emulsion layers sensitive to different colors, with dyes added during complex processing. Agfacolor followed in Germany in 1936. Color negative films for prints, such as Kodacolor in 1942, made color snapshots common by the 1960s. Kodachrome's distinctive saturated look, especially in slides, shaped how mid-century travel, family and magazine photographs looked; Kodak ended its production in 2009.

Milestones in color photography
YearProcess or eventSignificance
1861Maxwell's three-color projectiondemonstrated additive color
1907Lumière Autochromefirst commercial color process
1935Kodachromemulti-layer color slide film
1942Kodacolor negative filmcolor prints for amateurs
1976Eggleston at MoMAcolor accepted as fine art in a major museum
2009Kodachrome discontinuedend of a defining color film

Color becomes art

In the 1950s and 1960s, critics and curators associated color with advertising, magazines and amateur snapshots. Walker Evans called color photography vulgar in a well-known 1969 remark, though he later used Polaroid color himself. A few photographers, such as Saul Leiter in New York, made painterly color street photographs that were widely recognized only much later.

The turning point is usually dated to 1976, when John Szarkowski, director of photography at MoMA, exhibited William Eggleston's dye-transfer color photographs of everyday scenes in Memphis and the American South. Critics were divided; some found the subjects banal, ceiling light bulbs, tricycles, parked cars, while others saw a new way of seeing ordinary America. Szarkowski's catalog, William Eggleston's Guide, argued that color was integral to the images, not decoration. In the following years, photographers such as Stephen Shore, whose Uncommon Places (1982) recorded American towns and roads with a large-format camera, Joel Meyerowitz and Joel Sternfeld established color as a serious artistic medium. Since the 1980s, color has been the norm in contemporary art photography.

In the United States, the acceptance of color was closely tied to MoMA and the New York art world. After Eggleston's 1976 exhibition, a group sometimes called the New Color photographers, including Shore, Meyerowitz, Sternfeld and others, received exhibitions, grants and publication. The 1975 exhibition New Topographics at the George Eastman Museum, which included Shore along with photographers working in black and white such as Robert Adams and Lewis Baltz, presented the altered, suburban and industrial American landscape in a cool, detached style, a counterpoint to Ansel Adams's wilderness.

Film speed: ASA, DIN and ISO

Different countries once used different systems to rate film sensitivity. The American ASA system was arithmetic: doubling the number meant doubling the sensitivity. The German DIN system was logarithmic: an increase of 3 degrees meant doubling. The International Organization for Standardization combined them, so a film might be labeled ISO 100/21°. Digital cameras adopted the arithmetic ISO number.

Worked problem

Converting between ASA and DIN

The relation between arithmetic speed S and DIN degrees D is approximately \( D = 10 \log_{10} S + 1 \). What DIN value corresponds to ISO 100 and ISO 400, and how many stops apart are they?

Show solution
  1. For ISO 100: \( D = 10 \log_{10} 100 + 1 = 10 \times 2 + 1 = 21^\circ \).
  2. For ISO 400: \( D = 10 \log_{10} 400 + 1 \approx 10 \times 2.602 + 1 \approx 27^\circ \).
  3. The difference is 6 degrees; since 3 degrees equals one stop, that is 2 stops, matching \( 400 / 100 = 4 = 2^2 \).

Answer: ISO 100 is 21° and ISO 400 is 27°, two stops apart.

\[D = 10\log_{10} S + 1\]

The digital transition

The first digital camera was built in 1975 by Steven Sasson, an engineer at Eastman Kodak. It weighed about 3.6 kg, recorded black-and-white images of 100 by 100 pixels, 0.01 megapixels, onto a cassette tape and took about 23 seconds to record each image. Kodak, whose business depended on film, did not commercialize it. Through the 1980s and 1990s, electronic still cameras, digital backs for professional cameras and the first consumer digital cameras appeared. Adobe Photoshop, released in 1990, made digital editing widely available. By the mid-2000s digital cameras outsold film cameras, and Kodak filed for bankruptcy protection in 2012.

Camera phones appeared around 2000, and the iPhone in 2007 and Instagram in 2010 accelerated a world in which billions of people carry a camera and share images instantly. Estimates of the number of photographs taken each year vary widely by source and method, but many recent estimates exceed a trillion, the overwhelming majority with phones.

Worked problem

Megapixels and film: an equivalence debate

A 35 mm film frame measures 36 by 24 mm. If a fine-grained film can resolve about 50 line pairs per millimeter in practice, roughly how many pixels would be needed to capture that detail, assuming two pixels per line pair?

Show solution
  1. Horizontal: \( 36 \times 50 \times 2 = 3{,}600 \) pixels.
  2. Vertical: \( 24 \times 50 \times 2 = 2{,}400 \) pixels.
  3. Total: \( 3{,}600 \times 2{,}400 = 8{,}640{,}000 \), about 8.6 megapixels.
  4. With very fine film and lenses at about 80 line pairs per mm, the estimate rises to about 22 megapixels.

Answer: Roughly 9 to 22 megapixels depending on film, lens and technique, which is why estimates of film's digital equivalent vary so widely and why simple comparisons are misleading.

A flow diagram of a digital capture pipeline: lens, sensor with color filter array, analog-to-digital conversion, demosaicing, noise reduction and tone mapping, multi-frame merging, compression, and metadata including content credentials
A modern camera image passes through many computational steps between light hitting the sensor and the file you share.

Computational photography and the index

A modern smartphone does not simply record a single exposure. It may capture a burst of frames before and after you press the shutter, align and merge them to reduce noise and extend dynamic range, estimate depth to simulate background blur, apply scene recognition and selective adjustments to skies, faces and food, and sharpen details using machine learning. The resulting image is a computed estimate of what the scene looked like, informed by statistics from millions of other images.

This raises a theoretical question. If the index, the physical trace of light, grounds photography's authority, what happens when software reconstructs parts of the image? Some theorists argue that digital photographs remain indexical as long as they are derived from light recorded by a sensor; others argue that the boundary between capture and synthesis has blurred so far that every image must be treated with suspicion. Disputes over enhanced images of the moon on some phones in 2023 showed how controversial computational "improvement" can be.

Generative AI and authenticity

Generative AI systems can now produce photorealistic images from text prompts without any camera or scene. In 2023 the German artist Boris Eldagsen revealed that a winning entry in the Sony World Photography Awards was AI-generated and declined the prize, to provoke debate about whether such images belong in photography competitions. News organizations, platforms and competitions have since adopted rules about labeling AI-generated and AI-edited images.

Technical responses include content provenance standards. The Coalition for Content Provenance and Authenticity (C2PA), founded in 2021 by technology and media companies, publishes a standard for attaching signed "content credentials" to images that record their origin and edits. Some cameras, editing programs and platforms now support it. PHOT-320 discusses how news organizations use provenance; CRE-410 discusses AI tools for creators.

In the United States, the Copyright Office has stated that copyright protects only human authorship. Its 2025 report on copyrightability concluded that prompts alone do not give sufficient human control, while human selection, arrangement and modification of AI material can be protected. In Thaler v. Perlmutter, courts upheld the refusal to register a work created autonomously by an AI system. Meanwhile, lawsuits over the use of copyrighted photographs to train AI models, such as Getty Images' claims against Stability AI, have raised questions about photographers' rights in training data.

A bar chart with a logarithmic scale comparing approximate images made in different eras, from a few thousand daguerreotypes a year in the 1840s through millions of snapshots in the mid-twentieth century to over a trillion photographs a year today
Rough orders of magnitude of photographic production over time; figures are estimates and vary by source.

The networked image

Theorists of the networked image argue that photographs today are less objects than data in circulation. An image is captured, processed, uploaded, compressed, recommended by algorithms, shared, remixed, screenshotted and stored on servers. Its meaning depends on platform, caption, comments and the speed of scrolling. The artist and writer Hito Steyerl's essay "In Defense of the Poor Image" (2009) described low-resolution copies that circulate widely as having their own value, reversing the traditional preference for the pristine original. The photographer Joan Fontcuberta has used the term "post-photography" for images whose value lies in sharing and connection rather than recording.

These ideas return us to Benjamin's aura, Barthes's anchorage and Sontag's critique. Reproduction has become infinite and instant; captions and algorithms anchor meanings at scale; and the question of what photographs do to our experience of the world is more urgent than ever.

Worked problem

Storage arithmetic for a networked archive

A photographer shoots 40,000 raw files a year at about 50 MB each and keeps two backups in addition to the original files, following a 3-2-1 approach. How much storage is needed per year?

Show solution
  1. Original files: \( 40{,}000 \times 50 = 2{,}000{,}000 \) MB, about 2 TB.
  2. Total copies: three, the original and two backups.
  3. Total: \( 2 \times 3 = 6 \) TB per year, with at least one copy off site.

Answer: About 6 TB per year, a reminder that digital abundance creates real preservation costs that archives and individuals must plan for.

Practice: testing your own camera's processing

Photograph the same scene, such as a backlit window or a night street, with your phone's default camera and with a manual or raw mode that bypasses most processing. Compare the two files at full size. Look for differences in noise, sharpening, color, shadow detail, sky treatment and skin tones. If your phone records editing history or content credentials, inspect what it records.

Write a short reflection on whether the processed image is still a trace of the scene, using Peirce and Bazin. Most students find that the processed image is more pleasing but less faithful in specific ways, such as smoothed textures or brightened shadows, while the raw file is closer to the sensor data but needs interpretation to look natural. Both involve choices, made either by you or by engineers who designed the camera's software, which is exactly the point Vilém Flusser made about the camera's program.

Common mistakes

  • MistakeAssuming color photography began in the 1970s

    InsteadColor processes date to the Autochrome of 1907 and Kodachrome of 1935; the 1970s marked art-world acceptance

  • MistakeThinking ASA and DIN scales work the same way

    InsteadASA is arithmetic; DIN is logarithmic, with 3 degrees per stop

  • MistakeBelieving a phone photo is a single exposure

    InsteadModern phones merge multiple frames and apply computational processing

  • MistakeTreating megapixel equivalents of film as fixed facts

    InsteadEstimates vary with film, lens and technique

  • MistakeAssuming AI-generated images are automatically protected by copyright

    InsteadBoth Canadian and US law emphasize human authorship, and the law is still developing

Summary and key terms

  • Color processes date from the Autochrome (1907) and Kodachrome (1935).
  • Color was accepted as art after Eggleston's 1976 MoMA exhibition; Canada's Fred Herzog was recognized later.
  • ASA is arithmetic and DIN logarithmic; ISO combines them.
  • The first digital camera (1975) recorded 0.01 megapixels; digital overtook film by the mid-2000s.
  • Computational photography reconstructs images from multiple frames and learned statistics.
  • Generative AI and content credentials have reopened questions about authenticity and authorship.
  • Networked images circulate as data whose meaning depends on platforms and algorithms.
Autochrome
The Lumière brothers' 1907 color process using dyed starch grains
Kodachrome
A multi-layer color slide film introduced in 1935
Dye transfer
A color printing process prized for rich, controllable color
New Color photography
The movement of the 1970s that established color as an artistic medium
DIN
A logarithmic film speed scale in which 3 degrees equals one stop
Demosaicing
Reconstructing full-color pixels from a sensor's color filter array
Computational photography
Using software to combine and process captures into a final image
Content credentials
Signed provenance information attached to an image under the C2PA standard
Generative AI
Systems that create new images, text or other media from learned patterns
Networked image
An image understood as data circulating through platforms and algorithms

Practice problems

Work each problem on paper first, then reveal the answer to check.

  1. Who introduced the Autochrome, and when?

    Show answer

    The Lumière brothers in 1907.

  2. What made Kodachrome different from the Autochrome?

    Show answer

    It was a multi-layer film with three emulsion layers rather than a starch-grain screen.

  3. Which 1976 exhibition marked color's acceptance in a major museum?

    Show answer

    William Eggleston's photographs at MoMA, curated by John Szarkowski.

  4. Why was Fred Herzog recognized late?

    Show answer

    Color was not taken seriously as art, and slides were hard to print well until digital printing.

  5. Convert ISO 100 to DIN.

    Show answer

    21°.

  6. How many pixels did Sasson's 1975 digital camera record?

    Show answer

    100 by 100, or 0.01 megapixels.

  7. Using 50 line pairs per mm, about how many megapixels does a 35 mm frame hold?

    Show answer

    About 8.6 megapixels.

  8. What does a modern phone do when you press the shutter?

    Show answer

    It may merge several frames, estimate depth and apply computational adjustments.

  9. What is the purpose of content credentials?

    Show answer

    To record an image's origin and edits in signed provenance data.

  10. How much storage per year does the lesson's photographer need with three copies?

    Show answer

    About 6 TB.

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