It's great to be able to print at home because you can be more creative in your choices about what paper to print on and experiment with different versions of an image. There are only two kinds of printers widely used in home settings. Most large desktop printers—8.5 x 11 and larger-are inkjets. Many smaller, snapshot printers are thermal.

Inkjet Printers

The quality of inkjet printers has risen almost as fast as their prices have fallen. Their inks have also been improved so photos don't fade after a few months hanging on the refrigerator door. Some are said to last 200 years or so. Although the quality is high and the immediacy is great, printing photos is a time-consuming process, much of it spent preparing the images. When you make a print of one of your images on an inkjet printer, a lot is happening inside the printer. As the print head sweeps rapidly across the paper, thousands of nozzles in the head, each thinner than a human hair, spray tiny picoliter-sized droplets of ink to recreate the color of each pixel in the image. The tiny dots of color in each pixel visually blend into one of millions of possible colors depending on the number and distribution of each color's droplets. Inkjet printers use two approaches to ejecting the ink from the print head onto the paper:

• Bubble jets heat ink to vaporize it into an expanding bubble that forces ink out of the nozzle. Both Canon and Hewlett Packard use this technology.
• Piezoelectric print heads use a vibrating crystal at the back of each nozzle's ink reservoir to force ink out of the nozzle. This technology is used by Epson and in some printers from Canon.

A printhead can have thousands of nozzles, some over 30,0000. Generally, more nozzles increase the printing speed and spray smaller drops of ink so tones are smoother, especially in flesh tones and highlight areas. They also make possible a greater range of tones and smoother gradations.

Thermal Printers

A number of printer technologies use heat to activate dyes or pigments instead of using ink.

• Dye-sublimation printers produce photo-realistic continuous tone images that look like they came from a photo lab. Interestingly, this high-quality technology is also used in many small snapshot printers.

The "dye" in the name comes from the fact that the process uses solid dyes. "Sublimation" is the scientific term for a process where solids (in this case dyes) are converted into a gas without going through an intervening liquid phase.

Dye sub printers have their colored dyes in print-sized panels of cyan, magenta, yellow and black and require special paper that's designed to absorb the vaporous dye on contact. In many cases you buy the dyes and paper together.

During printing, separate passes are made across the print for each of the four colors—cyan, magenta, yellow, and black. A thermal print head containing thousands of heating elements vaporizes the solid dyes which then diffuse into the surface of the paper. Because the dyes are transparent, a cyan dot can be printed on top of a magenta dot to make a blue dot. By varying the amount of cyan, magenta, and yellow, any color within the printer's color gamut may be produced. On the final pass the printer applies a clear coat to protect the image.

A dye-sub printer can print a dot of ink for each pixel that has the same color and tone as the pixel in the image. In essence, a dot can be any one of 16 million colors. If the pixel is a light red, the printer prints a light red dot. If the pixel is dark red, it prints a dark red dot. When these dots are printed closely together, and then viewed from a normal viewing distance, they form smooth and even gradations just like silver-based photographic prints.

Because they can vary the density of each color, dye-sub printers don't have to use dithering to create a wide range of colors. And because there are no dithered dot patterns, the colors are applied in a continuous tone; hence the photorealistic quality.

• Thermal-autochrome, a process used in a few printers from Fuji, uses a special paper containing separate layers for the cyan, magenta and yellow pigments. Each layer is sensitive to a particular temperature with yellow having the lowest sensitivity followed by magenta, then cyan. The printer uses thermal and ultraviolet printheads and the paper is passed beneath these three times. On the first pass, the paper is heated to the temperature that activates the yellow pigment. This layer is then fixed by the ultraviolet printhead. The temperature is increased and the cycle repeated for the each of the other two colors although the last pass for cyan isn't followed by an ultraviolet fix.
• Zink (zero ink), the latest printer technology uses a paper, actually a plastic, containing embedded colorless dye crystals. As the paper moves past a heated printhead, each pixel is selectively heated to activate the crystals and form colors. Unlike the thermal-autochrome process, the paper is the only part that moves and it takes only a single pass through the printer. Because of this, a printer can be very small. Pocket sized printers use the technology and by the time you read this it may even be built into cameras.

Types of Printers

Printers come in a variety of forms with a variety of features. Here are the broad categories you are most likely to encounter:

• Desktop printers print on a variety of paper sizes from 4" x 6" prints up to 13" x 19" or so and print on all types of paper. Many also accept rolls of paper so they can print exceptionally long prints or panoramas.
• Mobile printers are like desktop printers, only smaller and lighter so you can pack them along with you. These printers are usually inkjets and can make prints up to 8.5 x 11".
• Snapshot printers, also called card photo printers, are small portable printers that print 4 x 6 inch prints straight from the camera. They are either inkjets or dye-subs and a few run on batteries for ultimate portability.

Laying Out Photos for Printing

Not all images are just sent off to the printer. There are times when you want more control of the process. For example, you may want to center the image on the page with well proportioned borders around it. This way, when inserted into an album, the image looks better and more professional than it would if printed off-center.

If you have ever had difficulty centering a photo on an 8.5 x 11 sheet of paper so there are even borders all around the image, you have been dealing with aspect ratios-the ratio between the width and height of an image. You'll find that a lot of photofinishers crop your images when they print them. Their dilemma is similar to trying to print a square image on a rectangular piece of paper. The only way to show the whole image is to print it so there are blank borders on the long side of the paper. If you enlarge the image so it fills the sheet, some of it has to spill over. In effect, you are cropping the image and that's what photo finishers do.

In addition to positioning a single image on the page, there are times when you want to print more than one image. How do you lay out the images so you can get as many as possible on each sheet of paper? There have been many programs developed to solve this problem, and layout features such as these are now integrated into most photo-editing programs. Basically, these programs provide a variety of layout templates. You specify a folder of images or drag and drop individual images into highlighted areas of the template where they are automatically sized—and often cropped—to fit. Here are some situations in which these programs or features are useful:

• Contact or index sheets show small thumbnails of each image along with other information you specify such as filenames and dates taken. You can use these indexes to manage your own collection of images or include an index along with a CD/DVD so a viewer can see what's on the disc without opening the files. Many programs let you specify the number of columns and rows of images you want on the sheet. The more images that you squeeze on the page, the smaller each will be. Many programs will now generate these indexes in HTML format so you can post them to the Web as a gallery, often with clickable links to larger versions.
• Picture packages print one or more sizes of the same image on each sheet. This feature is like an order form at a photo studio where you order one 8 x 10, three 5 x 7s and, twenty wallet sized copies of the same image.
• Printing smaller images. You don't always want or need to print large page-filling images. You can switch to smaller paper or layout 2 or more photos on a larger sheet and then trim them.
• Double-sided paper. When printing on both sides of double-sided paper you have to run the paper through the printer twice. You print the first image as you normally would. You then turn the paper over and feed in the other end for the second page so both images are facing the same way. When printing on two-sided paper that has a binding strip on it, you have to feed in the same edge for both passes so you have to use a photo-editing program or other software to flip the second image so it prints with the correct orientation on the page.

Cards of All Kinds

There are many paper projects you can create so one of your first steps should be to see what paper products are designed to run through your printer. There are hundreds of different types, some of which come perforated so you can easily tear them apart, and scored for easy folding. Avery dominates this market so their Web site is a good place to start. Many of their products are also available at local office supply stores.

Once you have the paper products to print on, the next choice is what software to use. Many photo-editing programs have templates that you can use to layout your photos and text. If you are experienced with a photo-editing program, that's really all you need. However, there are also card layout programs with templates, design wizards, clip art, fonts, and other features to help you easily create cards of all kinds. Sites such as Avery's also let you customize and print on Avery products directly from their Web site.

When making prints, a useful tool to have is a rotary paper trimmer that trims and scores paper. Trimming cuts paper to size and there are even special blades that add scalloped or deckled edges to the paper. Scoring creases the paper so it's easy to fold professionally.

Things to Consider

When selecting a printer it's hard to evaluate your choices based on specs or even a trial print at the store. This is one area where it definitely pays to "go with the crowd". Most professionals use Epson printers, however Canon is growing in popularity. Printers from other manufacturers are usually very good, and better than necessary for many people. Snapshot printers in particular, many of which use dye sublimation, can make beautiful prints. When choosing a printer, here are a few things you might consider:

• Costs. The cost of even the best printer is relatively small when compared to the cost of the materials you will run through it over its lifetime. Don't let your choice be swayed by a small price difference.
• Archival qualities. Prints made with cheap inks and paper will fade or deteriorate, even when stored in the dark. Most printer companies sell at least some models that use inks with archival qualities—creating prints lasting 200 or more years—provided you use their inks and papers.
• Compatibility. PictBridge is an industry standard that lets you print images from PictBridge compatible digital cameras and camcorders to any PictBridge compatible printer, regardless of brand or manufacturer, without using a computer.
• Connectivity. Most printers now connect to a computer's USB port with cables. Some printers also let you insert flash cards or connect directly to the camera with a cable so you can print without the computer. Some printers have a dock into which you insert your camera to make the connection. You then use the camera's display screen to select and print images. Just appearing is wireless WiFi, Bluetooth or infrared connectivity that lets you send images from the camera to a printer without a cable.
• Paper stock. The size and thickness of the paper that you can run through a printer varies. Check the specifications to be sure you can print on the paper you want.
• CD/DVD labels. Will it let you print labels on CD/DVD discs?