From Fax to Photoshop: The Complete History of Computer Scanners

How These Devices Evolved to Bridge Reality and the Digital World

Have you ever needed to quickly digitize a document or signed form? Convert printed photos for editing or sharing online? Backup the family photo album? Or recreate real-world objects in 3D?

If so, you likely used a scanner without even considering the rich history behind this technology.

In this guide, you‘ll learn:

  • How early fax machines paved the way for modern scanners
  • The world‘s first image scanner for computers
  • How both ancient and cutting-edge tech power these devices
  • The many ways scanners evolved for diverse applications
  • Why scanners remain so essential even in our digital age

Join me on a 150-year journey tracking the complete history of these portal devices that continue to bridge the physical and digital realms…

Prehistory: The Quest for Image Transmission

Long before computers existed, we wanted to instantly send images and documents far distances. This drove pioneering 19th century research into early facsimile (fax) machines.

The first primitive fax transmitter was developed in 1843 by Scottish clockmaker Alexander Bain. He cleverly repurposed clockwork mechanisms to synchronize the scanning process.

Bain‘s Fax Machine (1843)

ScanningSwinging pendulum arm with wire stylus scanned over raised metal plate image
SignalStylus contact variations over image created electrical signals
TransmissionSignals sent over wires to receiver device
ReceivingReceiver pendulum swung in sync, activating chemical paper to reproduce signals

This produced rough reproductions adequate to transmit simple line drawings and signatures. But synchronization limitations hindered performance. Subsequent innovators enhanced fax technology, including Frederick Bakewell‘s 1848 design incorporating improved synchronization from an actual clock.

Nonetheless, these early attempts only found niche use transmitting between two fixed devices. It would take the advent of digital computers to unlock the fuller potential of scanning technology…

1950s Computers & the Drive for Character Recognition

By the late 1950s, early digital computers were entering more widespread use for numerical and data processing applications. These could only intake coded alphanumeric data from punch cards, magnetic tape or primitive keyboards.

Inputting large amounts of text for business applications was already seen as an arduous task. Many researchers focused efforts on developing optical character recognition (OCR) devices. These would automate part of the workload by using photoelectric cells, phototubes and clever mechanics to identify typed characters on pages.

While fascinating electromechanical concepts were proposed, American computer scientist Russell Kirsch had deeper insights…

Kirsch realized emerging software algorithms on these new digital computers could also perform the character recognition task. But first, computers would need a fast way to input page image data to apply such algorithms.

This realization seeded the inventive spark leading to Kirsch developing the world‘s first computer image scanner in 1957…

1957: The World‘s First Image Scanner

While working at the U.S. National Bureau of Standards, Kirsch constructed that first scanner prototype for the SEAC computer (Standards Eastern Automatic Computer). This historic device used a rotating glass cylinder drum and photomultiplier tube to register light variations from images.

The SEAC Scanner

Key ComponentDescription
Photomultiplier TubeDetects & amplifies light reflections from image on drum
Glass DrumSpins image at high speed past tube
Analog-Digital ConverterTurns tube‘s electrical signals into digital data

The photomultiplier tube was an ingenious 1900s vacuum tube technology. Its interior metallic surfaces amplified faint electrical discharges triggered by light photons striking its aperture window.

Attaching a test image to the spinning transparent drum allowed it to scan the image line by line. The tube would detect even subtle bright/dark regions in scanned strips, generating electrical signals sent to amplifier circuits.

An analog-to-digital converter translated these signals into the 1s and 0s digital format for storage on disks or magnetic tape media.


Fig 1. Photomultiplier tube diagram [1]

Finally to display a stored scan, waveforms from tape fed a cathode ray oscilloscope. Modulating its electron beam intensity with signals generated a viewable image – the first computer visualization!

The World‘s First Scanned Image

To inaugurate his impressive invention in 1957, Kirsch chose an endearing subject – a photograph of his 3-month-old son Walden.

The resulting 176 x 176 pixel grayscale scan of the infant‘s face fittingly became the first image ever input into a computer system. Despite low resolution by modern standards, this breakthrough meant computers could now "see" the visual world!


Fig 2. Walden Kirsch photo and scanned image [2]

High Performance Scanning Arrives: Drum Scanners

While revolutionary, Kirsh‘s prototype had limitations. Hard to align and stabilize, it produced inconsistent, distorted scans.

Commercial drum scanners solved these issues by 1957 using sturdy steel frames, precision bearings and high torque motors. Spinning rigid glass cylinders over 2000 RPM enabled distortion-free scans.

How Drum Scanners Work

Attaching a photo or illustration onto the scanner‘s glass drum was the first step. Powerful internal tungsten or xenon arc lamps generated intense light flashes perfectly timed with each drum rotation.

The image modulates this bright scanning beam – absorbing some wavelengths while reflecting others. These light reflections strike a photomultiplier tube or similar sensor, converting brightness variations into proportional electrical signals.


Fig 3. Drum scanner diagram [2]

Precision Mechanics Ensure Superior Imaging

Drum scanner‘s tight mechanical tolerances gave them exceptional ability to resolve fine detail and tones. Photomultiplier tubes made them far more sensitive than human vision – registering over 65,000 distinguishable grayscale levels!

Combined with specialized optics and filters, leading drum scanners captured perfect reproductions of photographs, illustrations and film negatives.

While costly at over $50k, major publishers, archives and NASA relied on drum scanner quality for books, records and space satellite imagery.

The Democratization of Scanning

Drum scanners produced superb results but their substantial size, infrastructure needs and pricing meant ordinary offices or homes couldn‘t adopt this technology.

Making scanners compact and affordable enough for mainstream use motivated intense product research. Semiconductor and digital camera innovations provided this path…

CCDs & The Dawn of Flatbed Scanners

During the 1970s, specialized imaging chips called Charge-Coupled Devices (CCDs) emerged. These chips incorporated light-sensitive pixel elements which converted photons to electrons for quantifying irradiance.

Initially assisting digital cameras and astronomy, engineers soon recognized CCDs‘ potential to readings scans sequentially. Coupled with precise linear actuators from printers, CCDs enabled flatbed scanners.

Inside a Flatbed

Key ComponentsDescription
CCD light sensorDetects & digitizes reflected light
X-Y moving opticsScans CCD array over stationary document
White LED lightBright white illumination of document

These compact plug-and-play scanners used white LED lamps and mirrors to precisely guide optical paths onto a single-line CCD array.

Stepping motors shifted this linear sensor crosswise under a fixed transparent scanning surface – digitizing documents one strip at a time!


Fig 4. Simplified flatbed scanner optics diagram [3]

Going Color

Initial CCDs output grayscale readings. Obtaining color required separate red, green and blue scans.

RGB Filtered CCDs

This led to RGB filtered CCDs with alternating pixel sets for each primary color. Combining these three scans reconstituted lifelike color images!

Later models embedded sophisticated image processors enabling single-pass color scanning. Auto document feeders were also incorporated so users could simply load stacks of pages for completely automated digitization.

Flexible Deskside Digitization

Where drum scanners demanded dedicated operators and infrastructure, compact flatbeds fit neatly beside office computers.

Their speed, simplicity and affordability finally realized Kirsch‘s vision of effortless document/photo digitization for the masses!

Film Scanning – Digitizing Analog Archives

Photographic slides and negatives are hard to view and share in analog form. But once digitized, they integrate easily into modern digital workflows for editing and publishing.

This fueled demand for specialized film scanners with high resolution CCDs and backlights to register subtle tone and grain structure.

Dedicated Film Transports

Flatbeds lacked fine control and adjustments for transparent media. Thus dedicated film scanners incorporate film transports to advance frames precisely across sensors.

Some handle strips for sequential frame scans while others have transparency trays accepting slides, negatives or medium format sheets.

Technical Challenges

Digitizing film brings unique obstacles like dust, scratches and anti-halation backing layers.

Sophisticated algorithms deploy data interpolation, infrared cleaning and selective color channel blending to isolate and eliminate such defects.

Reviving Analog Archives

Today even modestly priced film scanners capture incredible levels detail. This finally provides mainstream means to digitize fragile slide collections before further degradation.

The technology likewise helps museums, journalists and relatives unearth analog photo archives for preservation and publication with minimal effort.

3D Scanning – Digital Recreation of Real-World Objects

While photos and documents have intrinsic informational value worth preserving, what about more arbitrary physical objects?

Creating digital records of these often requires more elaborate scanning methods falling under the umbrella of 3D scanning technology.

Measuring the Real-World

3D scanning aims to capture surface details and dimensions of solid items down to fine cracks, bumps and edges.

This produces expansive datasets with millions of coordinate point measurements mapping an object‘s exact size and shapes.

Various approaches exist like laser triangulation, structured light projection and computed tomography (CT) scanning.

Point Clouds – Representing Scanned Geometry

All methods output raw scan data as geometric point clouds with each point having an associated (X,Y,Z) coordinate location.

Grouping local points by proximity allows recognizing component surfaces and geometric features. Connecting these forms polygon meshes viewable as familiar 3D models.

Diverse Applications

Usability spans paleontology, medicine, quality assurance, computer graphics and more. Even hobbyists create 3D selfies!

Some highlight uses:

  • Industrial Design– Engineer product fits, ergonomics
  • Reverse Engineering – Analyze legacy parts lacking prints
  • Special Effects – Digitally recreate environments/creatures
  • Historical Preservation – Produce 3D records of artifacts
  • Medical – Fabricate precisely customized implants

3D data is now indispensable for these fields. Scanners digitize objects once practically impossible trace physically. The data in turn drives modeling, visualization, VR, rapid prototyping, CNC machining and other areas.

Scanners Today – Portals Between Worlds

This journey reveals how scanners evolved from early fax machines into optical digitization tools we now deeply rely upon in business, archives, science and creative applications.

Once strictly analog domains like film photography, documents and 3D objects can now effortlessly pass into the digital realm for editing and distribution. Scanners transitional role makes them a guardian technology ensuring accessible bridges exist between physical and electronic worlds.

So next time you drag and drop scanned files into an app or email, take a moment to appreciate the rich history of innovation these devices represent!


[1] Photomultiplier tube, Huub, CC BY-SA 3.0
[2] The First Image Scanned was of Walden Kirsch, Public Domain
[3] Flatbed scanner optics diagram, Daniel Christensen, CC BY-SA 3.0

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