Digital Focus: Clean Up Scanned Images

Feature: Banish Dust and Scratches From Scanned Images

If you’re anything like me, you’ve got a shoebox full of old prints that you’d love to scan into your PC–and you want to preserve those irreplaceable images from the inevitable fading process that’s slowly taking its toll. In their current state, my old prints are just collecting dust. If I converted them to digital images, I could easily share them with friends and family.

The scanning process isn’t perfect, though. It sometimes adds dust specks to the image, and scanners can’t magically remove scratches and tears from your pictures–at least not all of them. So how do you fix those problems? That’s what I’ll share with you this week.

Start With the Scanner

First, it helps to have a scanner that makes the situation better, not worse. Many modern scanners include special dust and scratch removal software. Trust me: It’s absolutely worth the money. The biggest name in defect removal technology is Applied Science Fiction’s Digital ICE, and it works really, really well. You can find Digital ICE in a number of scanners, including models from MicroTek, Minolta, and Nikon. You can’t buy the software separately, though, so don’t bother looking; it works with components resident in the scanner itself. Your best bet is to look for that feature the next time you go scanner shopping.

Use the Noise Filter

If you’ve scanned your photo and see dust specks or small particles in the digital image–maybe you don’t have Digital ICE in your scanner–then you’ll have to use the noise reduction filter in your image editor. Many programs have a noise filter, but you may have to search for it. In Adobe Photoshop Elements, for instance, choose Filter, Noise, Dust and Scratches. In Jasc Paint Shop Pro, try Adjust, Add/Remove Noise, Salt and Pepper Filter.

Most image editors give you some control over how aggressively they try to despeckle your image. Noise reduction filters let you specify the pixel size; the bigger the pixel, the better the filter is at eliminating dust. But if the pixel size is too large, the image becomes soft, and some pixels that belong in the photo might start to blur or disappear. Choose your filter levels with care. Start very small–or with the program’s default setting–and increase it in very small increments if it doesn’t get the job done.

Stamp Them Out

If the noise reduction filter doesn’t get the job done, you can take the matter into your own hands and stamp out the dust with a Clone Brush. Virtually every image editing program has one of these, and it’s handy for painting over unwanted debris with nearby bits of background. Done carefully, it can be difficult or even impossible to tell what you’ve done. Just choose a position close to the speck as your Clone Brush’s “source” and start dabbing. You can probably adjust the size of your Clone Brush; it’s a good idea to keep it small, or patterns in the background will start to become apparent if you paint away too many dust particles.

In Paint Shop Pro, the Clone Brush is the eighth tool down on the tool bar. To use it, right-click on the background to select the “source” location, then paint over specks by clicking the left mouse button.

Adobe Photoshop’s Clone Brush is the eleventh tool down on the left. To use it, define your “source” location by holding the Alt key when you click, then just use the brush normally.

Erase Scratches and Tears

Long, narrow blemishes–like tears and scratches–can be harder to eliminate. Some programs offer Scratch Remover-style tools, but I have rarely had much luck with them. Paint Shop Pro has a Scratch Remover (it lives in the same position as the Clone Brush in the toolbar, and looks like a trowel)–just select it and drag it across the length of a scratch. You can control the width of this tool, but it’s hard to avoid getting a fairly obvious smear through the image where the scratch used to be. And really, that’s no better than what you had to begin with. My advice? Rely on a judicious use of the Clone Brush to eliminate big glitches like tears and scratches.