Now that we can all scan our 4x6 color prints, we have come to realize that while it's fun, these pictures were printed at a greatly reduced resolution. We wonder if we can't find better images of our old family photos. You say you didn't know that color prints had limited details? I won't take up your busy day with the math, but I'll tell you that if you scanned them at 300 dots per inch (dpi) you'd likely get all of the detail that was available. If you are hoping to enlarge an old photo to 5x7 or 8x10, you're going to want to do two things: find the negative, and scan it.

Let's talk about scanning all of those delicate things—the slides and negatives that you found in a shoebox in Uncle Red's closet. There are two things to know. First, they have a lot of detail in them. Second, you want to avoid damaging them.

All of them have two sides, a film side that is clear or orange, and an emulsion side where the grains of pigment dried to form the image. Stay away from the emulsion side—you don't want to scratch it or get anything on it. It's a bit easier to clean the film side.

The Media
Black and white slides generally contain a lot more detail than the prints that were made from them. Many scanners have a light in the lid that can be used to scan negatives. My experience is that with the inexpensive scanners like mine, I can only scan things that are the size of 35mm negatives or slides. Larger negatives are out there, and they have exquisite detail, but I would need a different scanner to scan them because of the size.

Color negatives were made to be enlarged. The trickiest thing about them is that they are on a strip of orange plastic. If your scanner doesn't adjust for the extra orange, the colors will come out wrong. It turns out that different filmmakers have different shades of orange, so your “orange adjustment” varies by brand. If your scanner software doesn't let you choose the brand, you might want to think about getting a new one.

Color slides are one of my favorite things to scan. Slides get blown up (enlarged, projected) more than anything except movie film. Often, that 1.5 inch square slide is blown up to about ten feet on a side to project it on a wall—an enlargement factor of 80 to 1. Don't bother to try enlarging a scan of a 4x6 print that much; it will be a waste of time.

The Hardware
Speaking of enlarging scanned media, let's dive into the numbers and talk resolution. Resolution is typically measured in “dots per inch” or “dpi.” Most experts say that, unless there are unusual conditions, you won't be able to get more than 250 dpi from scanning a print—because that's all of the resolution that was used to make the print. But the negatives, they have a whole new universe of detail—and they can be scanned at 4000 dpi (yes, four thousand tiny angels dancing on the head of a one inch pin), and the results look sharp. You won't see jagged lines from computers “aliasing” and you won't see fuzzy, out of focus people—unless that's the way the photo was taken by Uncle Red.

If you have a flatbed scanner like I do, you're only able to scan at resolutions of 1200 to 2400 dpi. This is pretty good for scanning prints, and not bad for scanning negatives and slides, but it doesn't compare to the resolution of film scanners. They often are rated between 2700 and 4000 dpi. That's enough difference to get my attention—even if I don't want to buy the most expensive one.

According to the scanning guru, Wayne Fulton, the biggest difference in an expensive scanner (over $400) and an inexpensive one (under $250) is the “Dynamic Range.” I am pretty sure this means how much shading you can detect in the shadows of your slides, and the highlights of your negatives. Mr. Fulton cautions that you can't go by the numerical ratings that you see published by manufacturers, but rather you should pursue the best dynamic range available.

WARNING: This paragraph contains lots of numbers! Basically, if you consider 0 to be pure white and 4 to be very black, the difference between them is 4 – 0, or 4.0. If your scanner's “DMin” is 0.2 and its “DMax” is 3.1, then your dynamic range is 3.1 - 0.2, or 2.9. Why does that math interest you? Because a magazine or print, according to Fulton, has a dynamic range of less than 2.0, and a scan with an inexpensive scanner will reproduce that reasonably well. Film negatives are more like 2.8, and slides are about 3.2. If your scanner's dynamic range is 2.9, and you want to scan slides, you are going to lose some detail in the shadows; it's as simple as that.

So if you want to scan those slides and negatives, think about getting a film scanner to go with that flatbed scanner you already have. You can amaze your friends and family with the great pictures you can make with it.

Summary
To avoid scratching the emulsion side, you might want to consider wearing cotton gloves to handle them. You will look like Mickey Mouse, but your negatives will thank you.

And whether you buy a scanner for $200, $400, or $1500, remember: You get what you pay for, unless you get less.

More Information
For links and more information about scanning, please see the RootsWorks site.

If you want to discuss your scanning challenges, please drop by the RootsWorks Forums.

Registration is free, and I'd be interested to know what kinds of issues you are facing.

Beau Sharbrough is a product manager at Ancestry.com. His articles contain his own views and opinions and do not reflect any corporate policy or statement by the company. The RootsWorks series of articles focuses on genealogical applications for generic technologies. Beau would like to hear from you. Whether you have something to add or something to ask, please point your browser to www.rootsworks.com/forums and discuss this or any topic related to the use of technology in family history. Tell us about your experiences. Please note that he cannot assist you with your individual computer problems. Visit the RootsWorks website for links to previous articles and Beau's lecture schedule.

Copyright 2004, MyFamily.com.