The basic operation of your scanner, regardless of its make or model, can probably be summarized in three easy steps. One, place the original on the scanner. Two, open your scanning software and tell it to make the scan, usually by clicking either File > Scan or File > Acquire (or, even more simply, push the "Scan" button on the device itself). Three, save the resulting image to your computer, so later you can print it, e-mail it, or post it to the Web.
Getting the best scans, however, is not always so simple. Here are some ways in which you can guarantee you get the best possible results from your scanner.
Resolution, bit-depth, and file format
Before you start to scan, think about how you plan to use the final image. Is it going to be used in printed material? Will you perhaps print it out using your own photo-quality printer? Or is the image intended for on-screen viewing only, perhaps posted to a website or e-mailed to a friend or family member? Depending on the final product, you will want to set your scanner to capture the optimal image in terms of file size and picture quality. There are three basic settings you can adjust in order to do this.
Digital images are broken down and stored as pixels, dots of lights with their color value stored as a series of zeroes and ones. Resolution measures the number of pixels-per-inch (ppi), and thus serves as a guideline for the amount of detail available in the final image. Most scanners are capable of capturing an image in a grid pattern, 300 ppi wide by 300 ppi deep. This gives you a very high-quality, detailed image. But most image output devices (printers and monitors) are not capable of utilizing such fine detail. Average monitors, for example, only display at a resolution in the range of 72 to 96 ppi. Making a high-resolution scan of an image that will only appear on screen will result in an unnecessarily large file size. However, if you are planning on printing your image on a high quality printer, you will not be satisfied with the outcome if you made your scan with a lower resolution.
Bit-depth refers to the number of colors that the scanner will capture. A 1-bit scan will capture only black and white, a 4-bit scan will capture 16 colors, and an 8-bit scan will capture 256 colors. With a 16-bit scan you will get over 65,000 colors, while a 24-bit scanner will capture 16.8 million colors. The higher the bit depth, the better the color, but only at the expense of file-size. For online viewing, an 8-bit scan will be more than sufficient, but for color printing bump the scan up to the highest bit-depth available for your scanner.
- File format
The format in which you save your scanned image will be the final crucial choice you have to make. The two most common formats for image files are TIFF and JPEG.
- TIFF uses a lossless compression process, which means that you'll have no loss of detail in the image. You should use the TIFF format when you plan to print your image.
- JPEG, on the other hand, should be used if you are going to put your image on the Web or send it via e-mail. While some detail is lost in the compression process, it won't be noticeable when viewed on screen, and it provides a compact file size for speedy downloading.
Best scan tips
- Choose the best photo. While you can punch up color and fix some fuzziness with image editing programs, the better your original image, the better your final scan will be. Choose pictures that have good lighting and contrast to get the best results.
- Scan your photo in the orientation in which the image will be used. Some detail is lost when you rotate the image in your desktop publishing or image-editing program.
- Scan only what you need. Don't scan a whole image if all you need is a small portion. Your scanner software has tools to preview and select only the portion of the original that you want.
- Use your image editor, not your scanner software, to make adjustments to color and sharpness of your scanned image.
- Know your scanner software. If a manual is available, read it from cover to cover to know how to get the most from your particular software. Otherwise, spend time playing with the program until you get the hang of it.
- Practice, practice, practice. The more scans you make, the better you will understand how to get the best images from your scanner.