When it comes to digitizing images, scan photo resolution is key. Scanning old photos is crucial to preserve them and ensure they remain high-quality. It’s the number one quality factor in a photo-scanning project, and it’s easy to see why! Although they may appear to be of reasonable quality when viewing them on a screen. Low-resolution images begin to show their flaws in printing or enlargement. When the image is blown up, the pixel squares turn it from a photo to something resembling a Minecraft game screenshot.
Decoding Dots Per Inch
You can measure the quality of digital images in two ways: megapixels and dots per inch (DPI). The megapixel metric is on the optical side of the spectrum (to assess the output of digital cameras). The DPI number also comes into play when printing images. For example, you will likely see various DPI settings when printing a document or image in your print options.
A higher DPI normally means a better digital image to work with. A higher DPI scan produces more pixels for the best DPI settings, especially when scanning old photos, slides, and negatives. It is crucial for obtaining the best high-quality image. But DPI is more than just an indication of how many dots or pixels are in an inch of graphic space.
It also gives us a sense of the level of detail available in an image and the size of the final image file once done scanning. When insufficient detail is unavailable, the quality plummets as soon as you zoom in on the image. If there is a lot of detail, the image will likely be very good and hold up to zooming. But the image file you end up with may be too large for practical purposes.
For the best resolution when scanning photos, a recommendation is to use higher DPI settings. For example, 300 DPI is suitable for smaller photos, while 600 DPI or higher is for larger photos to ensure both the quality and size of the image are optimal.
The right resolution for your photo scan project
Before you begin a photo digitization project, it’s a good idea to first conduct an inventory of all your image sources. As a general rule, slides or negatives make for much better scanning sources than actual prints. The crisp details in a photographic image may get blunted in a print. Prints are also more prone to aging, discoloring and other blemishes that tend to make their way into digital images. These then have to be digitally erased using photo editing software. It is a time consuming and not entirely easy task for someone just starting with Photoshop.
It’s true that film does gather dust and grime over time. But this is easily wiped away with a lint-free cloth. In terms of DPI, most prints are in the 200 to 300 range. The typical negative or slide is usually well over 600 DPI. For original photos, you can scan them at 600 DPI if you intend to enlarge or crop the images.
Scanning at a higher resolution can lead to more image data than needed.
It should come as no surprise that scanning resolution is what sets good scanners apart from mediocre ones. Most people want to scan images in order to capture as much detail as possible for digital preservation and for making enlargements. In most cases, the higher the scanning resolution, the better the image quality of the final image. However, in cases where there is insufficient image detail to work with in a print. The scanner may not extract much of substance at a higher setting. In other cases, it may interpolate and fill in the gaps with empty or ‘’fake” pixels that take away from the sharpness of the image. So, choosing your resolution setting based on the source image is an important factor. Another point to keep in mind is that a higher resolution number involves more scanning time and calls for more disk storage space.
The importance of resolution and equipment in producing a high-quality scanned image cannot be overstated.
Just to provide an example, a small 4 x 4 print that is at 4800 DPI will yield an image that can occupy a whopping 2.2 gigabytes of hard disk space. This may be an extreme example but even lower resolution settings can create image files that are a few dozen megabytes in size.
The best scan photos resolution setting for your project tends to be what it is you’re trying to do. Time, quality, storage and your overall intent will ultimately dictate whether you scan your photos at 300 DPI, 600 DPI or higher.
Here’s a ScanCafe quick guide with some optimal resolution settings for different image formats:
A final note on backing up your digitized photos
You can’t be too careful when it comes to backup. Professional photographers often use high-quality storage solutions to preserve their digitized photos. Your laptop’s hard drive may be an obvious place to save your scanned images but it’s not necessarily the best permanent home for them. Secure your memories by doubly backing them up on another physical disk drive as well as online. With online storage costs having gone down considerably in recent times, there are many increasingly affordable options from the likes of Google, Apple, and Dropbox.