Guide to Scanning Old Photographs

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by Kay Spears

Do you have some old photographs you want to scan, but you’re not sure what format to use when saving them? Well, here’s the definitive answer: it depends. Yes, what format you choose for saving images depends on how you intend to use them once they are scanned. Here are some general guidelines.

  1. If the image is to be used for the Web/online, use JPEG, PNG or GIF. If the image is to be printed or used in a print publication, use TIFF.
  2. JPEG should be used when you need to keep the file size small and don’t mind giving up quality for a significant reduction in size. JPEGs are optimal for posting and transferring photos online. JPEGs aren’t suitable for images with text because crisp lines will blur. If you plan on doing any kind of restoration work on your photograph, JPEGs are not the format to use.
  3. PNG is ideal when you need smaller file sizes with no loss in quality. PNG supports alpha transparency (soft edges). PNG files offer greater compression and a much wider range of color depth than GIFs. However, not all web browsers support PNGs.
  4. GIF is a good choice for simple Web graphics with limited colors. GIF should rarely be used for photos.
  5. TIFF is good for any type of bitmap image. If you want to archive your family photographs, this is the format to use. This is also the format to use if you are planning on doing restoration work. Unlike JPEGs, TIFFs do not lose any compression when edited and resaved. I recommend that you scan your family photos as TIFFs; you can always reduce them to JPEGs for sending through emails or putting online. Always keep the original TIFF saved in a separate file. The downside: TIFF files are extremely large and take up a lot of storage space. However, the cost of disk storage continues to plummet while options continue to increase.
  6. BMP may be used for any type of pixel-based image. BMPs are huge files, but there is no loss of quality. BMP has no real benefit over TIFF, except you can use it for Windows wallpaper.

A final tip: for sharing a photo via the Web or email, scan at 75 or 100 dpi. A standard computer monitor is only 72 to 96 dpi, so it’s not necessary for anything larger. For printing, scan at 300 dpi. Printers have higher resolution than monitors. If you’re planning on enlarging an image, the general rule of thumb is double the resolution when doubling the size.

Article taken from the Genealogy Gems[1]: News from the Fort Wayne Library
No. 45, November 30, 2007