Archive for the Long Term

By Ken VanBree

I have a photograph of my great-grandfather that was taken more than 100 years ago. It is printed on tin. Tintypes became popular during the American Civil War because they were more durable and cheaper then other photographic formats available at the time. Their popularity faded when less expensive paper photographs became widely available.

I found the tintype in the attic of my mother's home in the Midwest. It had been stored there for 50 years, subject to dry, freezing winters and hot, humid summers. Despite the environmental abuse, the image of my grandfather was still easily recognizable.

I recently scanned in a number of family photos and put them on a DVD that I sent to my relatives. If someone finds that DVD in an attic 100 years from now, I wonder if they will recognize it as a repository of family photos, let alone be able to extract and view the photo of my great-grandfather.

The age of digital photography has made it easy to take a lot of pictures. This bounty of images has created another problem - how to store those images for the long term?

Fortunately the National Institute of Science and Technology (NIST) has addressed this problem in their report entitled, "Care and Handling of CDs and DVDs: A Guide for Librarians and Archivists." This 50-page report is a must-read for anyone seriously interested in archiving digital files for the long term. It includes a quick reference guide with practical tips for ensuring your CDs and DVDs last as long as possible.

To get the longest life from your archive disks, you should start with the highest quality disks available. Recordable disks (CD-R, DVD-R) with a gold reflective layer are recommended. Taiyo Yuden and Mitsui hold the original patents on recordable media and are still the choice of archivists, but beware of imitations. Lifetimes of 70 to 100 years are quoted for data storage on high-quality disks. Unfortunately, even the best media can degrade quickly if it is not handled properly during and after recording.

Because the recording layer is near the top (label) side of a CD-R, it can be easily damaged during the labeling process. I learned this the hard way when I used a fine-tip pen to label a CD of holiday music. Within two years the disk was unusable, due to damaged data that caused the CD to skip whole sections of songs. Broad, felt- tipped pens with water-based solvents are the best pens to use for labeling. If you can smell the solvent in your felt-tipped pen, it is probably bad for use on CDs.

The dyes used in recordable disks are sensitive to light. These dyes will degrade if subjected to strong light for long periods of time. Do not leave your archival disk on the dashboard of your truck if you want to be able to read it in 20 years, let alone two years. The NIST recommends that archival CDs and DVDs be stored at temperatures between 39 degrees Fahrenheit and 68 degrees Fahrenheit, at a relative humidity between 20 percent and 50 percent. The lower end of the range of temperature and relative humidity is recommended for extended-term storage.

Other tips for handling archival disks are to store them upright (book style) in plastic cases especially made for CDs and DVDs. Never touch the recording surface of the disk, instead grasp the disk by the edges or the center hole. Remove disks from their cases just before you plan to use them, and return them to storage immediately after use. When cleaning dirt from the data side of a disk, use a CD/DVD-cleaning detergent, isopropyl alcohol or methanol. Clean by wiping from the center of the disk to the rim. Never clean a disk by wiping it in the direction of rotation.

Remember that construction photographs are only useful to you if you can access them when you need them.

Following a few simple precautions when archiving your digital photos can help ensure that you have images to use in remodeling and repair work for years to come.

February 2006 Builder Architect Edition Issue

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