Number 251 - April 2004

Understanding Digital Image Resolution
from CCUG-PC Newsbits Chalmette, La, February, 2004
One of the most important factors in getting great prints from your digital photos is understanding digital image resolution. It may seem a bit complicated at first, but we've boiled down the basics to a few simple tips that will help make your photos look fantastic. What is a pixel?    Pixels are the basic building blocks of every digital image. Digital images are comprised of pixels lined up side-by-side, both vertically and horizontally. If the image is made up of many small pixels, it will look smooth and crisp. If it's made up of fewer large pixels, the image will be jagged and unclear, or pixilated. This translates directly to print quality--the more pixels in your photos, the better the prints will look. How are pixels measured?    The number of pixels captured by your digital camera's electronic chip is measured in terms of resolution. High resolution images are made up of more pixels than low resolution images (and thus result in better prints). Cameras' maximum resolutions are usually clearly indicated on the packaging or even on the camera itself.    If your camera has a resolution of 640 x 480 pixels or lower, it's considered a web camera and is best used for viewing images on a computer screen rather than making photographic prints. If your camera has a resolution listed in "megapixels" (millions of pixels per image), then it's suitable for getting prints. How many pixels do I need to make a print?    This depends on the size of the print. Fewer pixels are needed to make small prints than larger ones. To get high-quality prints in variety of sizes, it's recommended that your photos have at least the following minimum resolutions:	Wallet-size prints--320x240 pixels minimum (actual image size: 2x3")          4 x 6" print - 640 x 480 pixels          5 x 7" print - 1024 x 768 pixels          8 x 10" print - 1536 x 1024 pixels          16 x 20" print - 1600 x 1200 pixels          20 x 30" print - 1600 x 1200 pixels    Remember, the best prints require proper lighting, sharp focus, and the use of the highest available resolution setting. The web cameras described above are not recommended for print production. How do I set my camera's resolution?    Most digital cameras give you a choice of settings for image resolution. Photos taken on lower resolution settings take up less room on your memory card, but will not result in the best prints. For the best results, we strongly recommend always using the highest quality JPEG setting on your camera. Getting a larger memory card is a much better option than unsatisfactory, pixilated prints. See your camera's owner's manual for more information on the specific resolution options and how to set them. How else can I affect the quality of my pictures?    There are other ways you can affect the quality of your digital photos. For example, using the digital zoom function on your camera will result in lower resolution images. Unlike the traditional optical zoom, digital zoom is a software program that simply doubles the size of the pixels every time you zoom in. The result is fewer pixels, not a magnified image. You can also reduce image quality after taking the picture by cropping the photo. Similar to digital zoom, the tighter you crop the image, the more the pixels you remove, ultimately decreasing the quality of your final print. A better option is to get close to your subject when you take the photograph so cropping isn't necessary. Unfortunately, you can't increase resolution once the picture is taken, so remember these tips!
Number 251 - April 2004