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Photo scanning tip and tricks

May 29, 2007

By Al Fasoldt
Copyright © 2007, Al Fasoldt

   Things to do before you use your scanner
   The most important step is to make sure your computer knows how to show realistic colors. Whether you're using a Windows PC, a Macintosh or a Linux computer, the approach is the same: Adjust the display settings so that the computer can show at least 16-bit color. (This is called "thousands of colors" on a Mac.) Even better is 24-bit or 32-bit color (called "True Color" on many computers and "millions of colors" on a Mac).
   Next, be sure you're using a display resolution that's high enough to view your scans. If you have a 15-inch monitor, a resolution of 800 X 600 pixels is about as high as you should go without making things hard on your eyes. If you have a 17-inch monitor, 800 X 600 might not be high enough. Change it to 1024 X 768 if possible. If you have a monitor larger than 17 inches diagonally, try 1200 X 1024. I run 1600 X 1200 quite happily on my main computer. Don't be afraid to try that setting if your graphics card supports it.
   Ready for the good stuff? Here goes.
   Clean the scanner glass with Windex before every important scan. (There are other glass cleaners that probably work fine, but Windex is what I use and it is safe.)
   Let the scanner warm up for half an hour before you use it. Critical parts expand slightly and get closer into alignment when the scanner is warm. Do a few test scans (and delete the resulting images) to finish the warm-up.
   Scan each image at two resolutions, one low enough for computer screens and the other high enough for printing. The computer-screen images should be scanned at 75 or 100 dots per inch. The ones you want to save and print on your fancy color inkjet should be scanned at a resolution of 300 dots per inch. (WARNING: Scanning a normal-size photograph at very high dots-per-inch settings creates extremely large files. If you want to scan at 600 dpi or higher, start with a wallet-size photo and check the resulting file size before you scan anything larger.)
   Scan a treasured image at least twice and save the one that looks better.
   Always save (or "export," if your software calls it that) your scans in a "lossless" format. If you prefer uncompressed TIFF files or Adobe Photoshop (PSD) files, fine. Otherwise, save or export in Windows BMP format. BMPs are universal and are the least complicated of all possible methods of saving images. (That means a corrupted BMP file has a better chance of being rescued than a corrupted TIFF or PSD file.)
   Don't use a JPEG (also called "JPG") version of a scan for editing. Repeatedly saving edited versions of a JPEG image ruins the image quality.
   Scan only the image. If your image is smaller than the maximum size of the scanner image area, use the scanner's built-in software to crop the scanned section down to the image size. Leave no more than a tiny border of space around the image.
   Use the "black and white" setting to scan drawings and sketches (unless, of course, they are multi-colored images). This makes a much better scan and keeps the file size down.
   When you're finished scanning, get rid of all the temporary files your scanner creates. That means you should delete all unwanted images from the scanner's own "desktop" and then empty the scanner's trash can (If it has one) and the computer's own trash can . This applies to both Windows and Mac computers. You can easily lose 100 to 300 megabytes of disk space after spending a Saturday afternoon at the scanner, so reclaim as much as you can. What a scanner is, and why there are two kinds
   Flatbed scanners are scanners that make digital images out of flat items such as photos; film scanners make digital images out of slides and negatives. Flatbed scanners are sometimes able to scan slides and negatives, but they usually do a poor job. Flatbed scanners can also be used to turn typewritten text into a word processor document, using optical character recognition, or OCR. (That's not part of today's article.)
   Your scanner came with software, but much of the software that comes with consumer scanners is poor. (It's given away. That's your first clue.) Get your own software, learn how it works and get to know it well enough to trust it. Start with a good scanner driver -- VueScan from www.hamrick.com or SilverFast from www.silverfast.com -- and add good image editing software (Photoshop Elements from www.adobe.com). You can find Windows and Mac versions of all three.
   You also need a good image viewer. This is the step most people skip, but don't you dare. Get ACDSee Classic for Windows (it's roughly the same as ACDSee 3.1; do NOT get the current bloatware version of ACDSee) or ACDSee 1.6 for the Mac, both from www.acdsystems.com. Go to the "Digital photography and imaging" section of my Web site for articles on why you must have an image viewer and on how to set up ACDSee for proper operation. My site is at technofileonline.com.
A bit of color
   You can choose three color modes (or "bit plane" settings) when you scan. Which setting is correct is not as obvious as it might seem.
   Choose "color," of course, for all color images. But note that black-and-white prints aren't actually black and white; they're black, white and gray. This means you must set your scanner to "grayscale" when scanning B/W photos. (Don't use the color mode; that just wastes file space.) The third setting, called "black and white" by most scanner programs, is strictly for drawings, black-and-white newspaper pages, hand-written notes and that sort of thing.
   There are two ways to get a digital image from your scanner to your computer.
   The first way is to have the scanner (or the computer) save the picture as a file. You get a preview of the image in the scanner software, then click an icon to tell the scanner to create the scan and save the picture.
   Make sure the scanner saves the image in a non-destructive way. JPEG (also called JPG) is a lossy, or destructive, format; always use a non-destructive image format such as TIF (also called Tiff), PNG or BMP.
   The second way skips the file. Using a procedure called TWAIN, the scanner sends the image into one of your programs, so that it appears on your screen in, say, Adobe Photoshop Elements 2.0. That way, you can edit the image or crop it and then save it right inside that program. Be sure to avoid JPEG when you save the file.
   I recommend the first method if you have a lot of pictures, slides or negatives to scan. Get them scanned first and edit or crop them later. The second method is fine if you have only a few items to scan, but I prefer the first method. Here's why: I always, without exception, want to have an original scan for safety's sake. I never touch the scan that comes out of the scanner except to copy it. So I let the scanner create a file as the first step, then edit and tweak the copy.
Post-scan image tweaking
   A little encouragement first. Many people do only half the job when they scan photos. They take the scan and that's it. But the rest of the task -- editing the image after the scan -- is almost as important. So set aside time when you're scanning to finish the job with a good editing program.
   Tip 1: Crop the edges of every photo. Automatic color balance software is fooled by white borders at the edges of your scans. (They will nearly always be much whiter than any areas within the photo, leaving your image-editing software with the wrong information about the brightest parts of the picture.) Crop very slightly inside the visible edge of every scan, so that the top, bottom and sides do not have white borders.
   Tip 2: Save a copy of your image before every major change. (What's a major change? Not the crop I mention in Tip 1, surely. But significant crops are always good examples of changes you might not be able to undo. Another good example: Sharpening. Save a copy before you apply unsharp mask, for example.)
   Tip 3: Always adjust the color balance and black-and-white levels of each scanned photo. Most image editors will do this for you with two clicks. (Adobe Photoshop Elements 2.0 does this best. But be sure to run the Photoshop Elements auto-color fix before you run its contrast fixer. The software can't automatically adjust the contrast if the color is off.) Photos created by every consumer-level scanner need this kind of touchup.
   Tip 4: Don't resize an original scan in your software to make it larger; rescan the image at the larger size instead. "Upsizing" in software creates faked, or interpolated, pixels. What about making images smaller in software? While you can usually "downsize" images in your image editor without a problem, but I still recommend rescanning at the smaller size when possible.
   (Note: I'm not referring to a change in the dots-per-inch setting of a photo. That can be done easily in software. I'm talking about a change in the resolution, and therefore the file size, of a scanned image. Do that by rescanning the image at higher resolution. You can tell that your image has higher resolution if the file size is larger.)
   Tip 5: Never give up on a photo. You can often rescue pictures that are a little blurry by adding noise in your software (called "grain" in Photoshop Elements 2.0), for example. The noise fools the eye into ignoring defects. You can sometimes turn ugly color photos to acceptable black-and-white pictures by using the grayscale option in your software, too. You name your dog and your kids. Name your photos, too!
Sticks and stones will break my bones, but names?
   You have to give your pictures sensible names. Don't stick with the ones that the dumb computer (or even dumber camera) gives you.
   How do you do that?
   Ah, I'll bet you could see this coming. The answer is, "It all depends." The software you use with your digital camera probably gives you a way to rename your photos. If so, don't do it any other way. If you do it right there in the program that extracts the pictures from your camera, you're undoubtedly able to see the pictures while you rename them. That way you can make sure the names match the photos.
   But what should you do if you already have a lot of photos with crazy names stored in a folder somewhere? Don't put off renaming them with sensible names. As time passes, you're less likely to remember what each picture is all about.
   Your image-viewing software should solve the problem for you. If it's good software, it will give you a simple way of renaming your images. You should be able to click your mouse button on a thumbnail view (tiny image) of a picture and rename it that way or from a menu after the picture is selected.
   An image viewer is not the same as a photo editor or image editor. It's a small program that displays images quickly. The best -- ACDSee, available for both Windows and Macintosh computers, and Irfan View, a Windows-only program -- also let you view thumbnails, crop images and correct them in minor ways.
   And, of course, they also give you a quick way to rename your pictures while you are viewing them. if you don't have ACDSee or Irfan View, don't waste any more time. Go get one or the other.
Having fun with your scanner
   You can have fun with your scanner in many ways, too. Here are some suggestions:
   Do what I did for the holidays if you have grown children: Scan their old school report cards and homework projects, then print them out on art paper or heavy stock as birthday or holiday gifts. My kids have children of their own, so I had a joyful time scanning school artwork from the late '60s so that my grandchildren could see what their parents were doing in first and second grade.
   If your kids are still young, scan their hands every three months or so and save all the scans so they can be used as clever timeline art. An added idea: Make multiple copies of the best handprints and arrange them in a pattern that looks like a picture frame. Then frame your kids' pictures with their own handprints.
   Scan your coin collection. You can scan coins (and other small objects) one at a time as long as you crop the scan area in the scanner's preview window. (Scan the item, not the full background along with it.) Or you can scan many coins at once. The 3D effect will surprise your coin-collector friends when they see your scans.
   Scan your stamps. There's nothing wrong with scanning stamps one at a time, and the resulting images will store easily if you name them properly. I suggest doing both group scans and individual scans.
   Scan your CD album covers. If you (or your kids) know how to turn images into icons, the scanned album covers can be used as icons for MP3 versions of the CDs. (If that's not cool, my name is Mr. Bill and you are a peacock.)
   Scan your keys. Scan both sides. If your keys get lost and you don't have duplicates, a locksmith might be able to create new keys by examining your scans. (But store the scans where they won't get stolen.)
   Scan those certificates you get when you complete a training course or get an award at school, then print them out at a much smaller size (maybe 4 inches by 5 inches) and frame them for your desk. They take up less space and look -- dare I say this again? -- really cool.