Scanning Pictures

by Tom Mathewson

So. You got a scanner. Now what?

Well ... you can start by scanning those B-29 pictures and documents you have stored in that old box, the one that's collecting dust in the closet. Yeah, that one ... behind the shoes! You have some important stuff there, and you have to know how to scan it right and share it with everyone the right way.

And we'll show you how.

First, we'll touch on the preparations:

1. the goals you should focus on,
your hardware and software needs, and
the importance of learning how to operate your scanner and Windows Explorer.

Then we'll cover "the real stuff:"

4. the scanning process,
the best way to archive your pictures, and then
how to send them by e-mail.

The last section has

7, Advanced Tips for adjusting pictures,
8, links to other web pages with more info on scanning and graphics, and
9. Final Tips: the "last word" on the subject.

Keep in mind that this page is not an extensive tutorial! It's just a collection of quick tips to get you started. Once you're familiar with the basic process you can check out the links for more advanced tricks, like using the color balance for highlights and shadows or the curve and histogram tools for precise control ... but that's for later. First, let's cover the fundamentals.

1. Goals

Remember that you have two goals in the scanning and e-mail process:

Archiving: Digitally preserve the picture in accurate format. That photo is probably a piece of history, so save it as accurately as you can.

Sending: E-mail a copy of the photo in the smallest size possible yet still keep as much detail as you can. Copy it to a smaller size and the right format so that it downloads fast and people can see it.

2. Hardware and Software

You probably already have all the necessary hardware: a computer and a scanner. You also need graphics software to adjust, transform and save the pictures on your computer, but that usually comes packaged with most scanners. Larger graphics programs, such as Adobe's Photoshop, Corel's Photopaint and JASC's Paintshop, are also great to use.

Make sure your computer has lots of storage space. A large multi-gigabyte hard drive is usually enough for a while, but saving your archives to CD's is becoming the way to go. Good CD "burners" run less than $200, and blank CD's (they can hold over 600 MB each!) run for 80 cents or less. You can store a few gig's of stuff on your hard drive, then organize it into 600 MB blocks and move each block to a CD. It's a great way to free up space!

About colors ...

make sure your system can deal with full colors. For color pictures you'll need 24 bit color (millions of colors), which can show 8 bits of each color: red, green, and blue. 16 bit color (thousands of colors) can look ok in some cases, but it often falls short.

Black and white usually looks ok with 256 shades of gray (8 bit grayscale), but keep an eye on how it looks. If you see bands in the gradual shading areas, try to scan at 16 bit grayscale (thousands of shades of gray).

If you have a video card that sometimes has a hard time with color, then it might be running out of video memory. In this case you could lower your screen resolution to 640 X 480, and see if you can deal with 24 bit color. If you have this problem, then it's one of those compromises you'll have to struggle with until you get a better video card (nowadays they're cheap). I have an old system; it's my problem too!

... and what the heck is "TWAIN?" It's just the software that lets your computer, graphics program and scanner talk to each other. That's all. Just like the other stuff: your CD drive needs drivers, your video card needs its software, your mouse often needs it's software too. Like the "birds and the bees," they all do it.

But what does "TWAIN" stand for? "Technology Without An Interesting Name!" Really. They made some cool software but probably thought that pretentious acronyms were, well, pretentious.

Samuel Clemens would have been proud!

3. Know your equipment

First, Know your scanner! Learn how it works and practice with test pictures. If you don't know your equipment you're just going to ruin some files or break the machine. And don't believe the stereotype, real guys read the directions! (Remember how important it was to follow tech data?)

Second, learn to use Windows Explorer. It lets you create, rename, copy, move, and delete files and folders. You have to organize your pictures and files on your hard drive, so get very, very, very familiar with this program. Remember, "Windows Explorer is your friend!"

NOTE: This is "Windows" Explorer for exploring your hard drive, not "Internet" Explorer for exploring the Internet. They're sorta similar, but Windows Explorer is what you need here.

4. Scanning

A. When you scan a picture, at first set the resolution as high as you reasonably can. I often scan at 300 to 600 dpi. You don't have to save it at that resolution; you're just holding it temporarily at that resolution. Once it's scanned, then you can save it at 300 or 150 dpi or lower. This gives your computer more information when scaling it down in size, often making it look a bit clearer. It makes your scanner "earn its keep" for you.

If your machine crashes when you do this or takes a lot of time "crunching the numbers," your computer may be slow or not have enough memory to juggle the numbers. Restart your computer and don't run anything else except the scanning stuff. Remember, the two things that really put a strain on a computer are graphics and internet. If you still have problems, scan at a lower resolution.

B. Scan it at "millions of colors" if it's a color picture (24 bit color, which is 8 bits each for red, green, and blue), or at least 256 shades of gray (8 bit) if it's a black and white picture (If you see bands in the gradual shading areas, try to scan at thousands of shades of gray, or 16 bit grayscale). You want to preserve all the colors and shades of the picture. Exceptions: If you're scanning line art or a poster with just a few colors, you can reduce the number of colors and shades. But if you're not sure, go ahead and scan at the higher scaling and reduce it later if you'd like.

C. Descreening: If you're scanning from a newspaper or magazine, you'll notice that the picture is made of lots of dots. When it's scanned, however, you see a mottled interference pattern (called "moiré"). Use the descreen process of your scanning software to remove most the moire pattern.

D. Balance the exposure if it needs it; your scanning software should let you do this. When you preview the picture you can adjust things such as brightness, contrast, and highlight/shadows/midrange response. Then, when it looks reasonable, do the scan. It probably won't be perfect, but you can fine tune it once it's saved as an archive.

5. Archiving

Now it's scanned ... but it's not saved yet. You still need to make some more decisions about the picture.

A. You can save it at a lower resolution, but remember: you want to preserve as much detail as possible. A 4X6 close-up portrait could be saved at 150 dpi, while a tiny but detailed picture of over 20 crew members probably should be saved at 600 dpi. Decide for yourself what resolution you need.

B. Save it as a TIF file, such as "b29.tif". This format does the best job of saving details with no distortion. Granted, a TIF file eats up lots of space, but preserving your photo is important. Storage media is cheap now, and huge hard drives and CD burners make archiving your pictures more affordable than ever.

About other formats:

Avoid saving as JPEG or JPG. This is a "lossy" format: when it compresses files to save space during the saving process, it "tosses out" information. This happens even if you save it at 100%: that loses about 10 percent of its information. You'll see "artifacts" along sharp edges. Also, each time you save it, it tosses out more and more information. This is NOT the format for your archives!

GIF format: This is mainly good for line art. This format is limited to 256 colors or shades of gray, and can't deal with "millions of colors" or "thousands of shades of gray." If it's a black and white schematic or diagram, GIF is ok, and some B&W photos turn out ok. Otherwise, stick with TIF.

BMP format: This is an ok format, but TIF still preserves the picture a bit more accurately. Also, BMP is only Windows compatible, while TIF files can be read on all platforms, such as Macintosh and Unix. Still, BMP is a good second choice.

C. I usually leave the archive picture "as is" as far as exposure is concerned; normally I fix just the e-mail copy. Occasionally, though, you may have to do some more work on it.

6. Sending

Now that the picture is safely archived you can share it with others. But sending it as a big TIF file takes lots of time, and web browsers can't read TIF files. You have to resize it and convert it. Here's how I do it:

  1. First, copy the archived file to a working copy.

  2. Then, make it smaller in screen size. I usually size it somewhere between 300 and 500 pixels wide (or about 250 to 400 pixels tall if it's in a vertical "portrait" orientation).
    - NOTE: If it's going to Sallyann's website she wants it at no more than 500 pixels wide. Preferably smaller.
    - Also, if it's going on a web site, some people say it should be saved at 72 dpi (dots per inch) so that it loads properly. Others say it's irrelevant, that pixel and display size is important. Even we can't agree. Just read the links below and decide for yourself.

  3. Next, adjust the picture for brightness and contrast. Don't forget color and sharpness, covered in 7: Advanced Tips. Get it to where it looks good and clear.

  4. Now save it as a JPG file. Be careful with compression, though, you don't need much. Most space savings come from compressing it down to 90%; going further, such as 80%, doesn't save much more. Also, the more you compress, the worse it looks. Find the compromise that's best for you.
    - Remember, don't resave the JPG, that will just put more garbage in the compressed file. Here's a tip: I often size and adjust a TIF copy, save it, and then save it again as a JPG; if the JPG is no good, I just go to the already adjusted TIF copy and make minor changes from that. It saves me a lot of time; why should you have to start from scratch?
    - Note: Some black and white pictures look good as GIF files and take up the same space as JPG files (or less). Decide for your self which is best.

Try to get the file size down to between 30k and 80k; if it's too big try to resize it again from the archive. These size and format limits are especially important for Sal's e-mail list; some people have sent pictures that were in unreadable formats or were much too big. Nobody wants to spend 20 minutes to download just one picture that he or she might not be able to read! Remember: 30k to 80k files in either JPG or GIF format is the way to go.

Now that it's resized and saved in the right format you can e-mail it. Send it as an attachment to an e-mail, and it's done!

Note: Sometimes people ask for huge, high-definition pictures sent to them personally. You can do that, too! I've sent 2MB files in BMP format as well as huge TIF files to individuals on their request. But, never to the e-mail list! We need to keep the e-mail list traffic at manageable levels.

7. Advanced Tips

Once you're comfortable with the contrast and brightness functions you can try these more powerful tools that can do wonders with pictures:

  1. Color balance can compensate for a picture that's perhaps too blue or green.
  2. Some tools, such as Adobe Photoshop's color balance tool, also let you adjust shadows/midtones/highlights for more control over the exposure.
  3. If the colors are too intense or not deep enough, use the saturation or color depth tool to adjust them.
  4. Sharpening (or unsharp mask, which is better) is commonly needed since the scanner often loses sharpness during the scanning process. However, I usually leave the archive "as is" and sharpen the copies instead. The unsharp mask gives you better control than the sharpen tool, and makes the image look more normal. Remember: use this tool sparingly, a light touch is best.
  5. Curves is another powerful tool, giving you more precise control over specific exposure ranges.

There are more advanced tools and tricks you can use, such as using noise to improve pictures or using histograms, but I won't cover those here. Go to the links below for those tips and more.

8. Links

Once you're comfortable with these basic steps you can look for more in-depth advice. You can check out the following links for more advanced topics or special tips for your specific setup. Decide for yourself what tips work for you and what tips don't.

  • This site has lots of great information, from basic first-timer tips to advanced stuff on curves, luminance and histogram. It even has a wealth of information and links for scanners, even obscure models. Go here first!
  • The site focuses more on video screen captures, but this page has some good tips on working with the scanned pictures.
  • A few specific tips, including one in the black-and-white section about using noise to improve some pictures.
  • A collection of short tips, including curve tool as well as a good one on sharpening,

9. Final Tips

Here are probably the two most important tips I can give:

  • First, Take your time. Most mistakes happen when you're in a hurry. If instead you think about what you're doing and go one step at a time, you'll probably get it right the first time. Even if you make a mistake, you can easily back-track and fix it.
  • And second ... Have fun!! If you're not going to enjoy it, then why do it? But if you take your time and follow the steps above, you'll soon enjoy what you're doing. And if you enjoy it you'll probably do a better job on it.

So go ahead: take your time and enjoy it!


I would like to thank Scott Burris, Karon R. Dey, and Sallyann Wagoner for helping me get the facts right. And, of course, thanks to Sallyann for hosting this page for all of us.