Tuesday, June 1, 2004
Resizing Image Files
Resizing an image larger or smaller than the original file is a key digital adjustment
Sooner or later, you'll run into the challenge of resizing an image. Digital camera files often need to be larger for printing (they magnify in size quite well) or you may need to reduce a photo's size for e-mailing.
While you can resize an image when you first start working on it, this step is best kept for later as a finishing adjustment. The reason for the late use of this tool is that you should always keep a master image that has had all the necessary adjustments, then resize it for specific uses (be sure you have a backup file by doing a "Save As" on the original). A digital image often will have multiple files of the photo, each identical except for the size.
Image sizing should only be done to the master, then create the file "saved as" with a new name to keep it separate (e.g., GS-trillium-5x7.tif). Resizing an image that already has been changed in size can cause quality issues. Unfortunately, software manufacturers haven't placed the size/resize tools in the same location in the menus. You may have to check the Help function. It's under the Image menu in Photoshop and Photoshop Elements.
There are several important points to consider when resizing an image. First, remember that the size of an image affects quality only in terms of how big it can be printed. Second, changing resolution only (ppi/dpi with Resample unchecked) has no effect on quality. Third, we can't overemphasize it—don't sharpen the master; only sharpen an image after the file has been resized.
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