Unbelievable Madagascar September 14–October 1, 2007
				India Wildlife: On the Trail of the Tiger November 7–24, 2007
				Angkor Wat & Bagan—Temples of Cambodia and Myanmar January 17–31, 2008

Although digital photography offers an array of benefits, it also demands care in the field and at home to preserve images from accidental destruction. A faulty hard drive or defective Compact Flash card can scatter your pictures into the ozone, if you’re not careful. When out shooting, redundancy is key. You should always back up images in two places to forestall disaster. Once home, redundancy also plays a part—but deciding on the best media is tricky.

Don’t succumb to the temptation to just dump your pictures on your hard drive and pray for the best. Every hard drive will fail eventually. Even the good ones become corrupted as they dodder towards collapse. Just as in the field, back up everything you need to preserve in more than one place.

Adding hard drives to your system is the easiest way to back up your images. Every few weeks or months, send a copy of your newest images to the additional drive or drives. A program like Retrospect automates the process, recognizing and copying all the new data without overwriting any previously saved images.

A RAID (Redundant Array of Independent [or Inexpensive] discs) array works even more seamlessly and safely. A RAID consists of two or more drives that automatically save each image to more than one drive. (They can be configured to increase the speed of the system, but for our purposes, redundancy is the goal.) If a drive fails, simply remove it and install a new one, which will then write the missing data still contained in the other drives. While RAIDs work well, the initial set-up cost is significant, and replacing or repairing discs adds up over time.

Most people back up their images on recordable Compact Discs (CD-R) or, more recently, DVDs. CDs hold about 650 megabytes (including space allocated for disc management) while DVDs hold 6.7 gigabytes, about 10 times as much. The new double-sided discs hold 9.4 gigabytes. Since my Canon 1DS II produces RAW format images that produce 48 megabyte TIFFs, a CD holds only 10 images. DVDs are currently the best option if you work with big files.

In both formats a laser “burns” data into a layer of dye sandwiched between polycarbonate discs. A reflective layer, usually silver or gold, makes it easier for the CD of DVD player to read the disc. Silver reflects more light, but gold doesn’t degrade as fast. The layers can oxidize and lose information when subjected to heat, ultraviolet light or humidity. Even in ideal conditions, the best discs will start to lose information within 15 years, according to some authorities. In practice, expect the cheap off-brand discs to fail almost immediately. Always buy brand name discs and use the “Verify” feature on your burner. Then you know that you are starting with a good disc. What happens later is a matter of luck.

	James Martin

Fortunately, disc makers now offer both CDs and DVDs employing gold in their dyes to hold data, a much more stable medium. Matsui’s new DVDs use gold phthalocyanine for the dye layer. When combined with a gold reflective layer, these discs appear to be the most stable. Accelerated aging tests indicate that they will preserve data for 300 years in the case of CDs and 100 years for DVDs. Even if these numbers prove optimistic, gold discs represent the best option for long-term storage now available. No manufacturer offers double-sided gold DVDs yet, but I’m willing to bet they will arrive shortly.

No doubt storage technology will improve over time, so expect the media and equipment we use today to fall into obsolescence. If we take steps to safeguard our digital images now, however, they will be ready to transfer to tomorrow’s better technology when it arrives.

Be sure to check out James' latest book, DIGITAL PHOTOGRAPHY OUTDOORS: A Field Guide for Adventure & Travel Photographers published by The Mountaineers Press.

All images Copyright © James Martin