The advent of digital cameras has enabled many Americans to have access to vast amounts of digital pictures. Inevitably, some of these pictures will be of too low a resolution to print or post online, or a section of the image will need to be enlarged in order to be used effectively. Upon enlarging or raising resolution many images lose a lot of quality and sharpness. With a little practice you can learn to create higher resolution images with as little image degradation as possible.
Open your image in your favourite digital image editing software. If you don't have digital image editing software, you can perform an Internet search and will find quality free software for editing digital images. Most photo editing programs have the ability to analyse the image and display information about it for you. What you need to look for is the image size (in pixels) and the print resolution (in pixels per inch or ppi). Determine what your final image size should be both in pixels and ppi. Keep in mind that most printed images should be about 300 ppi and images on computer screens are generally 72 ppi. This means that an image with a width of 300 pixels will be one inch wide when printed, and 4.17 inches wide on a monitor. So if you need to have a two-inch wide print or an 8.3 inch wide image on a screen, then you would need to increase the horizontal resolution to 600 pixels.
Re-size your image using your image editing software's resize function. Depending on what software you are using, the resize tool will be located on different menus. The resize tool will present you with a number of options for resizing your image. Most importantly, the tool will display the current resolution and final resolution of the image. For example, if the original image has a resolution of 300x300 pixels and you need to double its print or display size, you would need to change the resolution to 600x600 pixels. Make sure that the “constrain proportions” option is checked if you have it. This protects the image from being resized in only one dimension.
Sharpen your image. The resulting image may be a little blurry, but this is normal. Should your software have it, use the “sharpen” tool to restore a little sharpness to your image. Alternatively, use the “unsharp mask” tool to better control the quality of your image-sharpening, although this tool requires a little bit of practice.
Save your image.When you save your image you have a few options as far as file types go. You can compress the image to save space, or leave it uncompressed to preserve quality. Compressed formats such as jpg or png are ideal for the web, while uncompressed formats like psd or tif are ideal for archiving.