Dear Listers: As the Society's Computer Interest Group is not meeting in December, I thought I would share this article about scanners. You may want to print it and put it in a binder for ease of reference and in anticipation that the Computer Group may discuss scanning in future. Happy Holidays, Lauren List Admin ...................................................... >From "Ancestry Daily News" ===================================================================== "ROOTSWORKS: SCANNERS," by Beau Sharbrough ===================================================================== Since I wrote about scanners in December 2000, some things have changed. For example, if you do a Web search on "new scanning technology" you'll find numerous entries related to scanning for explosives, not images. Scanners are electronic devices that convert paper documents into electronic images. They are very "numbery" toys --the resolution and image sizes, the number of colors--it's daunting to the newcomer. The images themselves are very big sets of 1s and 0s. Let's see if we can break these numbers down into something we can use. WHAT IS IT? A scanner shines a light on a document and records a lot of dots. If the image format is black and white, each dot is either black or white. Most scanners record 256 shades of each primary color. That takes 8 "bits" for each color. You'll sometimes see options for scanning in "24-bit" color. After those dots are converted to electrical pulses, they're converted into a number, by "digitizing." The point of bringing up the math here is that the files grow quite fast as we gather more information about each dot we scan. The user has a wide choice of resolutions, and the arithmetic to figure out how to get the best image would be a challenge for a math major. If you look at some of the explanations in the links section of this article, you'll see that you have to convert scanned resolution, in "dots per inch" to printed resolution, in "lines per inch," or screen resolution, in total dots per screen. A general guideline is that if you scan at resolutions that can't be output by your screen or printer, you will only obtain a slightly better looking image and you might take up a LOT more disk space. I've seen a number of cases where a genealogist has two census citations, where the ancestor's family lived in one state in one census and another state in the next one. If your scanner is a 600 dpi scanner, and you scan an image at 9600 dpi, the computer does something a lot like what genealogists do--they connect the dots with ones that they make up. From an information honesty perspective, I don't like the idea of creating records with data that I just make up, or that a machine just makes up for me. I'd suggest that you not exceed the rated resolution of your scanner when creating historical records! NAME TWO OF THEM There are several types of scanners, but in my opinion the only ones to think about buying are the flatbed scanners. Hand-helds are a little harder to get good images from. There is a pen-type scanner that will read lines from documents, but I still prefer making copies and scanning whole sheets. There are some big differences in price, but these days you can buy a better scanner for under $50 than you could buy for $1,000 in 1990. The biggest differences in any two scanners these days are the price and the connection method (parallel, SCSI, and USB). WHAT'S THE DOWN SIDE? There aren't many down sides to scanner use. Of course, if you get a scanner you're going to want to have a lot of free disk space to put all of those pictures on. You'll have to learn to choose which images to keep and how to let go of the other ones, which is a big challenge for a genealogist. In times past, there was a problem with complicated setup, but that's much easier now. HOW DO I KNOW IF IT'S NOT WORKING? I only see two kinds of problems: bad connections and wrong settings. As a rule, if you set up your scanner properly it will keep working all the time, but occasionally I have the scanner turned off when the PC comes up and the scanner won't work. When that happens, restart the PC. If you scan a document with the wrong settings, you can usually either re-scan it or change the image in a graphics program. WHAT IF I CHANGE COMPUTERS? Scanners come with three different pieces of software: a device driver that tells the computer how to talk to the scanner; a scan manager program that actually controls the scanner from the computer (and is where you choose the resolution and picture type); and a special edition of a graphics program to catalog, print, and clean up the images you make. If you change computers, you will want to reinstall the drivers and scan manager software. Be sure you can hook it up--some PCs don't have the same connections. This is especially true with SCSI connections. WHAT'S THE GENEALOGY TIE-IN? Converting pictures of family members and images of historic documents to computer files gives you the option of linking those files to your genealogy records about those people, and of e-mailing them to your relatives and colleagues. MORE ABOUT RESOLUTION - PPI, DPI, LPI If you get a headache from doing a lot of math, skip this section and get your kids to do your scanning. There are three important points to cover about resolution: --- file sizes, --- variations in resolution for cameras, monitors, and printers, and --- enlargement. File sizes can get out of control if you're not careful. A 3"x5" image scanned at 200 pixels per inch in black and white contains only 600,000 pixels, and takes up 4.8 million bits. By the time you store it on your hard drive in JPG format, it might not take more than 25K of disk space. But scan that same 3"x5" image at 300 dots per inch in RGB format (24 bits per pixel--8 red, 8 blue, 8 yellow) and you have 32 million bits. Some scanners and printers boast of 2400 DPI resolution--try that and you'll obtain over 4 billion bits. Hard disk space is relatively cheap, but unless you're starting an archive or printing a magazine, you can generally scan at 200 DPI and be happy with the image. One of the first things that I had to learn after I acquired a scanner was the difference in the size of an image when I saw it on the screen and on the printer. Let's say that you scan a 4"x6" photo at 200 dots per inch. If your printer has 600 dot per inch capability, and you don't add dots when you print, the printed image will be one-third the scanned size, or about two inches wide. Put the same image on a monitor, which has a resolution of about 72 dots per inch, and you'll see an image about three times as large. The important point is that knowing where you want to display a scanned image might have an impact on the size that you scan it--printers and monitors are different enough that you might find it reasonable to create two different scans. Enlargement is a great feature of computer images, but one that can trick you. If you have a 35mm slide, and want to print it out at 1200 dots per inch on your photo printers, 7 inches wide, you'll need a whole lot of dots. In a case like this, you might wish for a scanner with 5,000 dot per inch resolution. What you can do, to make the full page photo of your ancestor's head in a group photo, is enlarge the image 500 percent, and choose a resolution that is related to your printer's best quality. WHAT SHOULD YOU DO? Should you scan at a higher resolution than you can print? Some people say no, as if there were a Moral Imperative to preserve dots. Wait, I'm climbing on my soapbox. Maybe you should scan higher anyway. Perhaps you will be buying a new printer someday. Or perhaps you want to save the images for one hundred years and you don't know what technology will be available then. What you should do is make your own informed decision about how to make these tools work for you, the way you want. Period. Okay, off the soapbox. LINK ME UP (More Stars Is Better) --- ZDNet Reviews *** Great product evaluations, tips, and explanations for beginners. --- Scanning overview **** A good explanation of the basics of scanner technology. --- Scantips **** Just like its name, lots of scanning tips, including a method for getting the best pictures. --- PPI, DPI, LPI and Color Depth Unraveled**** A page that offers tips and techniques about resolution. WHAT ELSE? Some scanners support transparency adapters (a backlit replacement for the scanner cover that lets you scan slides and transparencies, about $150) and sheet feeders (a mechanical replacement for the scanner cover that lets you scan a stack of papers, about $150). Digital cameras are great for taking pictures of people. They're not so good for making images of documents or old photos because you can't get closer than a couple of feet and the picture comes out too small. One other function of scanners is to convert paper documents to text, using a process called Optical Character Recognition, or OCR. Next time--graphics file formats. ___________________________________________________________________ The RootsWorks series of articles focuses on genealogical applications for generic technologies. Beau would like to hear from you at mailto:[email protected], but due to the volume of e- mail received, he is unable to answer some e-mail messages. Please note that he cannot assist you with your individual computer problems. Visit the RootsWorks website (http://www.rootsworks.com/ ) for links to previous articles and Beau's lecture schedule. FOR A PRINTER-FRIENDLY VERSION OF THIS ARTICLE, e-mail it to a friend, or submit your feedback on it, just go to: http://www.ancestry.com/rd/prodredir.asp?sourceid=831&key=A661101 and click on the appropriate icon in the sidebar. ............................................ REPRINT POLICY: We encourage the circulation of the "Ancestry Daily News" via non- profit newsletters and lists providing that you credit the author, include any copyright information (Copyright 1998-2002, MyFamily.com Inc. and its subsidiaries.), and cite the "Ancestry Daily News" (http://www.ancestry.com/dailynews) as the source, so that others can learn about our free newsletter as well.