The BBC News Technology section has an interesting item about a project to preserve lost computer file formats dating back to the 1970s.
I wish these people had been around when I was abandoning my old Panasonic word processor and buying my first Mac. I bought my Panasonic when an Apple computer was very expensive. It had a 5cm high LCD screen and could read/write to floppy disks, though it formatted them in an esoteric way. Every word I wrote for about four years, fiction and non-fiction, was written on that machine, but (of course) the disks and files were unreadable on the next computing platform I used.
Just choose File>>Export from an image editing programme, and you can see the size of the problem. JPEG (JPG) has been a web standard for many years, in spite of the fact that it loses information when it compresses files. Other formats, like .PNG and .GIF can also be found on the web. Apple’s old bitmap format was .PICT, while Microsoft’s was .BMP. Professionals tend to use TIFF (.TIF), though the Photoshop format is also widely supported, and PDF can be used for images as well as text.
Any one of these file formats, falling into disuse, could cease to be supported in the next generation of your web browser. Most upper-end digital cameras allow you to work on files in the RAW format that comes out of the camera – except this changes over time, and differs between cameras, so your iPhoto or your Aperture/Photoshop has to keep up with the changes.
In the lifetime of Mac OS X, Apple have used at least three different file formats for screengrabs: PNG, PDF, and TIFF. I’ve got an application called Tinkertool that allows you to choose an alternative (I chose JPG), but most people stick with the default – perhaps not noticing how often it changes.
As with image files, so with text files, vector graphics, databases, and music or video files. Keeping everything working in 10, 20, or 30 years time is going to be a tough job.