Dear Listers: As the Society's Computer Interest Group is not meeting in December, I thought I would share this article about graphic files. 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 graphics and scanning, in future. Happy Holidays, Lauren List Admin >From today's "Ancestry Daily News" ===================================================================== "ROOTSWORKS: GRAPHICS FILE FORMATS," by Beau Sharbrough ===================================================================== The more I research for these articles, the less I know about computers. For example, I found dozens of graphics file formats. Genealogists faced with a stack of photos and a scanner, don't always know which format to use. Let's develop some simple guidelines. WHAT IS IT? Image files fall into two categories: "raster" and "bitmap" formats. Raster images are built up from lines, circles, and other shapes. Bitmap images are built up one dot at a time. A bitmap image is converted into dots called "picture elements," or "pixels." The pixels are stored in computer files using "binary digits" or "bits" - - long strings of 1s and 0s that don't look anything like your grandmother. There are several flavors of graphics file formats for storing images. For example: --- If your picture is black and white, it takes one bit to store one pixel. --- If your picture is "true color" it takes 24 bits to store the color information for one pixel, and more bits for the brightness or darkness. Some formats are "lossless," meaning that you can save them as much as you like and you won't lose any data. Others are "lossy" and the more times you save the picture using them, the more you will degrade the image. Typically, lossless formats produce larger files, so you will want to save "master" copies of pictures in a lossless format, and you'll want to use a lossy format for e-mail and the Web. Since image files can be so large, some formats include "data compression" features, so that they make smaller files than those that don't compress the data. Please don't confuse loss and compression, they are altogether entirely different things. Due to compression, files of the same image in different formats will have widely different sizes-which means it takes widely different amounts of time to display them on websites and to send and receive them as e-mails. You can learn a great deal about this subject by browsing the links included below. NAME TWO OF THEM Some of you may be surprised, but I won't be discussing the BMP and PCX formats. They are only used on Windows platforms, and in my opinion, others do the job better. Here's a partial list of formats: BMP-Bitmap. "Bee-em-pee". Windows requires it for desktop wallpaper in older versions. Only reason to ever use one. Not used on Mac. PCX-PC file format. "Pee-see-eks". Not used on Mac. JPG-Joint Photographic Experts Group. "Jay-pee-gee or "jay-peg". Smallest files, it's good for copies of your master. Generally best for Web photos. JPEG2000-A new specification based on "wavelet" compression. Not widely used, but holds real promise. GIF-Graphics Interchange Format. "jiff" or less often "giff". Second smallest files made here. Generally best for Web artwork, images with less than 16 colors. TIFF-Tagged Image File Format. "tiff". The most widely supported format, makes the biggest files (unless you ask for compression and that method varies from program to program), and Macs can read them. PNG-Portable Network Graphics. "ping". A growing format for art, but not all browsers recognize it. MNG-Multiple Image PNG. WHEN IT WORKS, WHAT DOES IT DO? The picture looks good! Actually, when it works, you get the best balance of image quality, disk space usage, and waiting time (if it's on a website or in an e-mail). Typically, for e-mails and websites, use JPG for photos and GIF for logos, artwork, or other images containing 16 colors or less. For a "master" copy, choose between TIFF and PNG based on what your software can do, and which ones you like the best. Both are "lossless" formats. WHAT'S THE DOWN SIDE? The down sides are issues of size, and of loss. By loss, I specifically mean that if you take an image, and save it to a JPG or GIF format repeatedly, you will eventually see that the image quality suffers. One of the things that frustrates me the most is to find that the particular program I'm using either can't read or can't write in the format I prefer, so look at your choices under "Save As . . ." to be sure that you know what you can do. Also, things change pretty quickly in the computer world, and these specs, in computer terms, are getting old. Since we last covered this topic two years ago, very little has changed in the format world. During that time, the CPU speeds for sale in the stores have tripled. So has the capacity of hard drives. The speed improvement between USB and USB 2.0 is 20 times. But there are no improvements in the compression rates or qualities of the most used graphics file formats. Isn't this the 21st century? Why, in the name of the Jetsons' dog Astro, is there even a need to compromise between file size and image quality? WHAT'S THE GENEALOGY TIE-IN? Making computer images of photos and documents is a constant occupation for genealogists. Putting together a scrapbook of images of ancestors is a great thrill. I should add that I've received at least a dozen e-mails since my last article from people who love to use their digital camera to photograph documents on research trips. Some readers even included examples as attachments, and I admit that I found them easy to read. Digital cameras have come a long way, and will probably soon outrank scanners as the method that family historians use to create images from the documents and photographs that they find at the homes of their relatives and at record repositories. All of the genealogy programs that I've seen in the past few years allowed the user to link the images to the people in their database, to print scrapbooks, include photos on wall charts, include them on webpages, and make a slide show. LINK ME UP (More Stars Is Better) Scantips **** http://www.scantips.com/ Just like its name, lots of scanning tips, including a method for getting the best pictures. Has some great info about formats, file sizes, strong and weak points. Examples of how the appearance of each format differs, blown up so you can tell it. Graphic File Formats at a Glance **** http://acomp.stanford.edu/acpubs/Docs/graphic_file_formats/ A Stanford University site that compares formats, and suggests when to use GIF vs JPG. UseNet Graphics File Formats FAQ *** http://www.oreillynet.com/search/?keywords=%2Fgff-faq%2Findex.htm This is aimed at experienced computer users, but it has some good information about converting from one format to another. Besides, these questions are frequent! WHAT ELSE? PDF files are technically graphic images, but they are almost never listed as graphic file formats. Some graphics programs will save in this format but typically you have to buy an "Adobe Acrobat Writer" to make them. The new JPEG format, JPEG2000, has both a lossy and a lossless capability. The file sizes are much smaller than the current JPG format. Presently, it's only a published specification. I tried a plug-in for Photoshop, and was impressed that the experience matched the hype. Maybe, when we talk about this subject in two more years, users won't be forced to compromise between file size and image quality. ____________________________________________________________________ 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 at: http://www.sharbrough.net for links to previous articles and Beau's lecture schedule. The site will soon feature discussion forums for your computer experiences related to these articles. 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Lauren: Great article. Thank you for posting it. I'll add it to my material for graphics and scanning. Happy Holidays! Gene Pennington http://homepages.rootsweb.com/~genepenn/ Researching Pennington - Wann - Stickney - Tankersley - Lancaster - Justis Member of these genealogy associations/groups: Pennington Research Association - http://www.penningtonresearch.org Marin County Genealogical Society - http://www.maringensoc.org/ BARUG (Bay Area Roots User Group) - http://homepages.rootsweb.com/~barug/ National Genealogical Association - http://www.ngsgenealogy.org/ California Genealogical Society - http://www.calgensoc.org