Why a Higher Scanner Resolution Isn’t Always Better
Particular scanning tasks have recommended resolutions. You may be wondering why not simply use the highest resolution of your scanner at all times. But a high scanner resolution may not give you the best digital image:
Too much resolution wastes valuable hard drive space. A 4 x 5 image scanned at 200 samples per inch (spi) has 800,000 pixels and can be up to 6.4MB in size. Scan the same image at 2400 spi, and you can end up with a 76.8MB file!
It wouldn’t take long to fill up a hard drive with those 2400-spi babies.
High-resolution (hi-res) images take a long time to scan. Depending on your scanner model, you might be able to scan that 200 spi image in ten seconds or so, but you’re sure to wait for two or three minutes when scanning the same photo at 2400 spi.
High-resolution scans of prints don’t contain any more useful information. When you scan at a resolution higher than you need, you’re just capturing the grain of the paper or perhaps the film used to make the print. You’re also getting beautiful close-up details of any scratches and dust.Scanning an image at a high resolution can just highlight the paper’s grain.