Anyone undertaking a genealogy scanning project, or just scanning a single old picture for Throwback Thursday, might have wondered what resolution is best for the particular thing about to be scanned.
Wonder no more! Here are some quick resolution tips for scanning old photos and documents from the Family Tree University Digitize Your Family History online course, which starts Monday, Nov. 23.
In general, the higher the resolution (measured in dpi, for dots per inch), the more you can enlarge the image without getting that grainy, pixilated look. But higher-resolution files also are bigger and hog space on your computer or in your cloud storage, so you don’t want to scan everything at the highest-available dpi. Instead, go with these rules of thumb:
- If you plan to post the digitized image to a blog or website, the standard is 72 dpi.
- If you want to print the image at its original size, scan at least 300 dpi.
- If you’re scanning old letters and other documents to archive, use 300 dpi. (But notes, receipts and papers you’re not intending to archive are fine at 72 dpi.)
- If you plan to view the scanned photos on your HDTV screen, use a minimum of 300 dpi for 4×6-inch originals, and higher dpi for smaller originals.
- If you want to enlarge the photo up to double in size (for printing or on-screen zooming-in and examining), scan it at least 600 dpi.
- If you’ll want to more than double the size of the original photo, go even higher with the dpi. At 900 dpi, a 4×6-inch printed photo turns into a 16×24-inch digital image.
- If the original photo is small, scan at 600 dpi or higher. If you scan a 2×3-inch photo at 1200 dpi, for example, it will become a 16×24-inch digital image without losing quality.
- If the original is a tintype or daguerreotype, scan at 1200 dpi.
- If you don’t know how the digitized photo will be used or you’re scanning it to archive for posterity, scan at least 600 and up to 1200 dpi.
Remember that you can always downsave a copy to a lower resolution, but you can’t add image quality without re-scanning the original.
Family Tree University’s Digitize Your Family History four-week course, starting next Monday, Nov. 23, has guidance from Denise Levenick (author of the book How to Archive Family Keepsakes) on how to digitize your old family photographs, precious documents and heirlooms.
This course will help you achieve the peace of mind that your family’s visual memories and their associated stories are safeguarded against fire, weather damage, loss and family discord. And you’ll be easily able to share these mementos or publish them in book form. Learn more and register for the course at Family Tree University.