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All About Pixels

Film has given way to pixels, and we have gone from dog-eared color photographic prints and moldy 35mm slides to storing our family photos on piles of CDs, and now into the nebulous world of cloud storage. What was once the province of the darkroom became a daylight venture, and the tools of the craftsmen became available to anyone brave enough to wade in.


While early scanners still required highly skilled graphic arts professionals to operate them, they greatly sped up the process of capturing artwork for color separations. Early analog models used photomultiplier tubes and a daunting array of knobs and buttons to perform the same job that had been done by the huge cameras. The first scanners were petite only by comparison to their gigantic camera ancestors: Many could easily dwarf a Volkswagen. It was necessary to mount artwork on a heavy, clear plastic drum and then painstakingly ensure that there was no dust or a trapped air bubble to mar the scan. Scanner operators came from the ranks of color-separation cameramen, and their years of finely honed instincts for camera separations translated well to the newer methods. Thus began the move to digital capture and storage of image information, resulting in our devotion to the pixel and the advent of digital retouching.

In the mid-1990s, improvements in the capabilities and simplicity of flatbed scanners, coupled with the widespread usage of Adobe Photoshop, led to a major change in the way color separations were performed. It was no longer necessary to mount artwork on cylindrical drums, and the numerous knobs were replaced with onscreen buttons and dialog boxes. The digital imaging revolution was underway. Suddenly, people who weren’t sure what color separation meant were making color separations.

As flatbed scanners have become more automated and less expensive, it’s relatively easy even for novices to make a decent scan. But the more you know about what constitutes a good image, the better the chance you can create a great image from the pixels generated by your scanner.

Digital Cameras

Today’s scanners capture transparencies, negative film, paintings, and illustrations and express them as pixels. High-end digital cameras now rival—or exceed—the ability of film-based cameras to capture photographic detail. The image captured by the camera is a digital original, so there’s no need to scan a print. Of course, the better the camera and the photographer, the better the image. The rapid evolution of digital image capture is such that today’s cellphones take pictures with more inherent information than the earliest digital cameras.

While conventional camera film—such as 35mm transparencies—must be scanned to be used on your computer, digital camera images can be downloaded directly to the computer and used immediately. Digital photography also cuts out the middleman. Unlike film images, digital images don’t have any grain, although an image photographed in low lighting conditions may tax the resolving capabilities of a digital camera’s sensor, resulting in unwanted digital noise.

Consumer point-and-shoot cameras deliver captured images as JPEG, a compressed format. There are degrees of compression, from gentle to aggressive, and you may never notice any visible artifacts betraying the compression. But higher level “prosumer” cameras and professional digital cameras can deliver images in the Camera Raw format, which is subjected to minimal processing by the camera. While you cannot place a Raw file directly into Illustrator or InDesign, Raw images can be opened directly in Photoshop and saved in another format, such as Photoshop PSD.

Raw files can be color corrected in the Photoshop Camera Raw environment without losing additional information. For example, an image shot under daylight conditions but with the camera’s white balance set to fluorescent lighting can be corrected with one click in the Camera Raw environment without the loss of information that would be incurred by using a Levels or Curves correction in Photoshop.

If you are a point-and-shoot photographer who just wants to capture moments from a quick vacation, you may consider Raw files to be overkill. But for professional photographers, Camera Raw is a powerful and flexible format, often enabling the recovery or enhancement of details and tones that would be lost in a JPEG file.

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