11 The Digital Darkroom
Contents
Introduction to the Digital World
Introduction to the Digital World
The digital revolution has descended on photography with all the speed we’ve become used to in computer-related progress. Remember records? Those big disks of vinyl covered in grooves that could produce the scratchiest sound ever heard? It’s possible that you’ve still got a bunch of them and the turntable to play them on, but now you just slip a CD into your player and listen to the clear, clean sound of digital music. The ability to choose a song at random, skip through it, fast forward or back, program the sequence—what luxury! And you have to go a long way to damage them. Well, that same sort of convenience, clarity, and stability is now available to any photographer who owns a computer.
I’m sure that most people have become familiar with the phrase “to digitize” thanks to the music industry. Simply put, there are two ways to store and display information: one is “analog” or continuous, the other is “digital” or discreet bits. An analog is a continuous, unbroken stream of information as in a curve on a graph. There is an infinite amount of information in the curve, since you can extract that information at infinitely small divisions. It gives, by far, the greatest amount of information. Digital information comes in discreet amounts or levels as opposed to the continuously variable analog information. There is a finite amount of data, and that’s what makes it possible to store and manipulate it on a small personal computer.
Digital creates the illusion of a continuously variable analog in much the same way that movies create the illusion of motion with discreet still images. It’s a matter of spacing. If the digital information is made up of steps that are sufficiently close together, then the difference is so small as to become unnoticeable. Or at least that’s the theory. There are musicians who claim they can hear the difference between a digital and an analog recording. If the steps are not close enough together, it is quite easy to tell a digital image from a standard photographic image. (The standard photograph is, to be sure, a digital image, made up of discreet clumps of silver. There are just so many of them—more than any but the very largest computers could store and manipulate.) So you can see where this is leading. The problem for digital photography, especially for the amateur, is how many digits the image can be broken down into and still be manageable. In the computer world, the question is always “how big a ‘file’ can you deal with?”
Image-file size, or the “resolution” of the image, is a function of something called dpi or dots per inch. This term reflects an effort to retain some of the familiar terminology used in the printing industry. There, dots refer to the dots on a printing screen that make up the image: the more dots, the finer the image. In mechanical printing, the size of the dots as well as their density make up the variations of the image. In digital imagery, it is the height of the step, its value, and the density of steps that make up the variations of the image. The dots are recorded by individual sensors called charge couple devices, with one sensor for each dot. One reason digital recording devices are so expensive is because of the large number of these sensors required to get a high-resolution image—lots of dpi’s. Each machine has an upper limit to the amount of resolution it can record or output. The higher the resolution, the better the image quality.
Adobe Photoshop. This computer screen displays an image being altered using Adobe Photoshop. The background image is unmanipulated; the foreground shows the image after it has been altered. Note that the large lamppost has been removed.
Digital Equipment
How do you digitize an image? How do you get digital information into your computer? You can do it directly by using a digital camera. These cameras, which are becoming more common and less expensive by the day, allow you to take and store in the camera a number of photographs. This number depends on the storage capacity of the camera and the resolution of the image. Many of the digital cameras allow you to choose the resolution or dpi of the image, and thereby the number of images you can store in the camera. The higher the resolution, for instance 600 × 600 dpi, the bigger the image file and the fewer the images that can be stored. Some cameras have removable storage cartridges that give you the ability to take a virtually unlimited number of photographs. You might even want to take along a laptop and input, or “download,” the photographs direcdy into the computer. The current problem with affordable digital cameras is the amount of resolution they can provide. This level of resolution is usually not enough to produce a high-quality image, especially when reproduced in a large size.
The method most people use to have their photographs digitized is to have them “scanned.” Traditional formats, produced with a photographer’s old tried-and-true camera are then subjected to the scanning process. Transparencies, negatives, or prints can all be scanned. A scanner is a device that records your photograph in digital form. There are two kinds of scanners: drum and flat bed. Drum scanners are complex and extremely expensive. They are used mainly by service bureaus, businesses that provide digital input and output. The photograph is attached to a rotating drum and then scanned as it spins under the sensors. Flat-bed scanners are much less expensive and well within the range of most commercial photographers. The photograph is placed on the bed of the scanner and is scanned by a moving bar much like that in a photocopy machine. Many scanners allow you to preview the digitized photograph, called the “scan,” before you enter it into the computer. Then you can use the scanner’s software for an initial manipulation of the image for contrast, color, density, and so forth.
Another way of obtaining digital scans of your photographs is to send the film to a developing house that will develop your film, scan the negatives and send you back a CD full of your pictures. You then put the CD into your computer and access or open any image directly into your image manipulation software. Once you have a digital image in your computer, you can do virtually anything with or to it. After all, you’re just changing a number associated with a dot.
When it comes to image-manipulation software, there is really only one: the great, the wondrous, the ever-changing Adobe Photoshop. This program will allow you to play with your image in standard ways (contrast, color, density, cropping). In addition, it will give you an almost unlimited freedom to add, subtract, twist, turn, and otherwise play with your photographs.
Photoshop is quite expensive and requires a computer with sizable memory, both internal and external, but there are a number of far less expensive programs that give you quite a variety of things to do to your photographs. Some page-layout programs have image manipulation capabilities. Once you have a digital image, you can import it into almost any document in your computer. Page-layout programs allow you to make documents combining photographs, illustrations, and text. They are used extensively in the design industry, but they can also be a lot of fun at home.
Digital Camera. The Epson Photo PC 500 is a 640 × 480 dpi camera that stores up to 30 images at maximum resolution.
Digital Scanner. The Agfa Studio Star is a 600 × 1200 dpi, moderately-priced scanner. Adapter for scanning transparencies is optional.
Printing the Digital Image
Once you’ve altered or enhanced your digital image, you will want to show it to the world. You can have people look at it on your computer screen, but that’s not very convenient. Instead, you’ll want to avail yourself of one of the many output options. There are printers that work with your computer to produce a very credible image without spending a lot of money. Ink-jet and bubble jet printers are the most popular. They allow you to use many kinds of plain paper stock, such as watercolor paper, to change the look of your photograph. You can even put your photograph on a transferable medium and make t-shirts! A much higher-quality image can be achieved by using a laser printer. Naturally, this higher quality is reflected in the printer’s price tag.
The closest thing to a true photographic output is the dye-sublimate printer. It is quite expensive, but it gives a beautiful photographic print on special paper. Again, no chemicals are used, not even the inks of the jet printers. Dye sublimate printers use a film roll that must be replaced after a certain number of prints have been “processed.”
If you want to make your own prints, a machine called an imagesetter will make a continuous-tone negative. Imagesetters are very expensive and are usually found only in service bureaus. These machines will also make slides, if you prefer to view your photographs by projection.
In the context of digital imagery, the entire concept of the traditional darkroom has now been replaced. No dark room, no chemicals, no handling negatives, no touching at all, except for keyboarding. A very large change has been effected in a very short period of time. But get used to it—the digital world is here to stay.
Ink Jet Printer. The Epson Stylist Color 500 is a 720 × 720 dpi plain-paper printer.
Dye Sublimate Printer. One of Kodak’s dye sublimate printers and the special paper and thermal ribbon needed to print with it. An expensive unit, but imagine the luxury of adjusting an image with your computer and then making a print by just pressing a button! This type of equipment is being constantly updated, and you may be able to purchase a used one at a reasonable price.