Using and archiving primary resources is a large part of many of the projects at our school. Writing autobiographies or biographies and recording the stories of family members and veterans often include taking or scanning images of objects, letters, or photos. When scanning the question that is eventually asked is what format do I save in? to which I answer, save as a .jpg of course! right?
But a strange course of recent events made me question my answer. First, I lost over 1,500 digital images taken on vacation in London. Gone…not stored on my computer, not on my external drive, and the one disk labeled “London” won’t open. Second, I remember a video clip I saw over at Free Technology for Teachers on Data Rot. My ears pricked up when the acting Chief of Prints and Photographs at the Library of Congress commented that 16 million photos, prints and posters would be scanned and saved as TIFF files. TIFF files?
Lastly, my mom gave me this image. On the back of the photo she wrote “the Pin up Girls”. (One of them is me and I’m not telling which one!) The photo is one a very few that I have of my vacation with my sister when I was five. I want to save a coy of it, so do I take the LOC’s advise and scan and save as a TIFF or go with the good, old JPG. What is the difference in file formats? I decided to investigate. Here is what I learned…
JPEG-Joint Photographic Experts Group.
If you’re working with a photograph or a highly detailed graphic with lots and lots of colors, and storage space is limited, JPEG may be your best choice. JPEG files make use of 16 million color providing the integrity of the color is preserved when the file is saved. Using lossy compression images saved in JPEG format are reduced in size by only removing color information that would not be normally detected by the human eye. However, each time a JPEG file is resaved in JPEG format more information is lost. Images composed primarily composed of lines or text may appear blurry when saved in a JPEG format.
GIF-Graphics Interchange Format
Pulling from 256 color GIF formats work well with images composed mostly of text in small font size, line drawing, black and white images, or blocks of a single color tone. If you save a highly detailed color image in a GIF format you may see major changes in color value, or tone. Individual GIF images can combined into an animated images with the use of an animation editor.
PNG-Portable Network Graphics
If you use a Mac and use the Grab utility or take screen snaps using Apple Shift 3, you’ve probably noticed that the snaps are saved as PNG files. PNG files have the best qualities of JPG files and GIF files. PNG files are compressed the same way JPG files, but result in files 5%-25% smaller then in a GIF format. Unfortunately some browsers do not displays the PNG format.
TIFF-Tagged Image File Format
If there was a Gold Standard for scanning formats, TIFF would be the awarded the title. The choice for most commercial and professional needs, TIFF files are not compressed; the result is no loss of data from original to digital format. The downside is file size; TIFF files can be much larger then a JPG file of the same image. If you are working with detailed and/or historic images, or you have a photo that you will be reprinting or re-saving multiple times, you may want to archive your images in a TIFF format.
In the end I followed the LOC’s advice. I saved as a TIFF file at 1.1mb compared to the 336kb of space needed for the JPG format.