Image file types

Similar to Omeka being an appropriate CMS for certain collections, the utilization of different file types depending on the needs of a digital collection are important as well. I believe that in order for collections to function to their full potential, knowledge of the underlying digitization technology is essential. Not only is it important that digital items are accessible – they need to be appropriate in terms of size and quality. As digital libraries/collections become more pervasive, the need for librarians to become comfortable with digitization standards is increasingly necessary. Having knowledge of these standards allows information professionals to make pertinent -and consistent- choices when building collections.

I have to say that I was surprised to see that Barrett uses jpegs as the “ultimate format” for storing his digital photographs. Although the idea that jpegs lose information every time they are opened is a falsehood, they do in fact lose information as multiple generations of the file are created (i.e., copy and save one file, then copy and save a second one from the first, and so on…). Barrett even mentions this in his explanation of file types. Yes, jpegs are ideal for web-purposes, but they certainly aren’t the best way to save valuable, high-quality images. Coming from a background in photography, it was a little troubling to see Barrett’s recommendation. Saving image files as jpegs have their advantages and are necessary for certain situations, but tiffs really are an ideal format for preserving all the information in an image file. As others have noted, the storage process that the Wisconsin Uprising Archive undertakes is a wise choice (three files: the original jpeg, a lossless tiff and a web-appropriate size jpeg). This system ensures that there will always be a version of a file that retains every bit of information possible while also addressing the need for reduced resolution files necessary for web-based applications.


2 responses to “Image file types

  1. The great thing about digital libraries is that there doesn’t need to be a single file type for all purposes: as Keely points out, a three tiered system can be used with files that meet several different needs, whether its quick-loading thumbnails for cell phone browsing, or bandwidth-chewing .tiff files. JPGs offer a lot of useful qualities that make them the ultimate in practical images, perhaps, but as you say, they are not the best for long term storage.

  2. Great thoughts here, especially regarding the issue of what constitutes archival/preservation-quality digital photography. For my high-quality camera work, for instance, I import my files in a RAW format to give myself the most options in terms of file format later on. The tradeoff is that these files are _huge_, and require a great deal of storage space.

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