DIY Photo Resizing: 3 Options for Best Photo Resize Results
If you use digital images, here are the best ways to enlarge (or shrink) them to ensure that you achieve the maximum potential in the photo, and avoid "stair-steps" and other undesirable artifacts.
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Digital Photographs: Sizes and Resolutions ExplainedEvery digital image is made up of little, single-color squares called "pixels". And every digital image has an actual dimension or grid size, e.g. "28 x 28".
Look at the image of the soldier on the left - just the portion on the far right. Its size is 28 pixels across by 28 pixels down. You can count them (in this special blow up). The full portrait on the left? It is 473 x 600 pixels (reduced to fit into the space on this webpage). What about the file size in kilobytes (KB) or megabytes (MB)? Important right? Not really. You can mostly Ignore it. Seriously. There is a relationship between the number of pixels and the file size, but it's complicated by things like levels of JPG or PNG format compression - which vary from picture to picture. So ignore file size and concentrate on pixels. And the photo's resolution - ppi or dpi? You can mostly ignore that too. The question of resolution is seldom ever important when viewing or publishing digital images (screens and websites ignore the resolution and just look at pixel dimensions). However, if you are scanning or printing something you will need 300 pixels for every inch of print you want. Double that (600 dpi) and you double the size of the image when printed. Moral: Know the dimensions of your photo in pixels! |
Photo Resize Method 1: Rescan the Original
Photo Resize Method 2: Resize your photo online
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Photo File FormatsA note on photo file formats
Some scanners and resizing tools let you choose the file format. What should you choose? Photo archivists have long recommended saving files in the uncompressed "TIFF" format. And you can't go wrong doing that. But they are large and a lot of applications can't read them. For images you plan on printing, we recommend the "JPEG" format, using the maximum quality or "minimum compressed" settings. Tests have shown that the human eye cannot distinguish between TIFFs and highest quality JPEGs. For images you plan on using online and with screens, we recommend the computer-optimized "PNG" format. And if you plan on emailing them or delivering them as attachments or on a flash drive then you can use the Adobe PDF format. |
Photo Resize Method 3: Download a Resizing ToolThere are some good free choices, and some good paid choices. On the "free" side: "SmillaEnlarger", allows you can drag and drop images from your desktop, zoom in to enlarge, choose a custom size, or fit to a particular aspect ratio like 4:3 or 16:9. You can't change the look much, but you can "sharpen" the image if it's a bit soft (or blurred) and reduce noise.
The Smilla interface (shown left) limits your "save as" options to those that match the file - jpeg or png during our tests. Overall, comparing PicResize and SmillaEnlarger with Photoshop, these two free, easy to use programs came out very well. |