Given the likely future of digital data storage, your best preservation for color photo images is in just that form: stored data. Barring the total breakdown of society and human civilization, there will continue to be institutional data preservation facilities available to everyone.
Putting your precious digital photo files "into the system" is likely to be the most surefire, long-term way to preserve them. Of course, you will always be able to produce physical media prints by whatever process is extant at the time you want to view the images, using whatever is the best cost/performance technology you wish to pay for at that time.

It is convenient to keep a backed up, working copy of your digital photo files in your own possession for the near term; this can be on the best media currently available now, optical or magnetic (see previous articles about the longetivity of CD media), but remember that any physical media is subject to deterioration, so you want redundancy. Keep more than one copy and keep the copies on different types of media.

Be careful to use data formats conformant to widely accepted, non-proprietary standards. Do not count on your digital camera's native format to be around for long. Get those images copied from the camera manufacturer's file format into some well-known open-standard format.

For physical prints, you have many choices, but it's a fact that all the color processes create prints that suffer from deterioration over the years. Most color dyes are not stable, especially when exposed to light. You can consult photographic experts to find the best "archival quality" print media and inks. Whether the color image is infused into the media, or layered onto the surface is not as important as the fundamental permanence of the chemistry used.

I personally know that Kodachrome transparencies, protected from light and humidity, last in excellent condition at least 60 years. Maybe longer - time will tell. I can scan my Kodachrome transparencies made around WW2 era and get good prints by various processes. Then I gently put the transparencies back in their special containers, out of the light. Even still, I know that those transparencies are aging - the dye particles are being hit by a few random bits of radiation and breaking down, from year to year. In a few centuries, these images will probably lose detail and color.

For color prints, there are a number of high quality processes from the photographic industry as well as the commercial printing world. These prints can be made from digital files just as easily as from traditional photographic negatives or positives.

In recent years, makers of inkjet, dye sublimation, and color laser printers have claimed archival permanence for their inks (toners). It remains to be proven, but such prints might be a good, low-cost way to keep your photographs at least for a decade or two.

If you can live with monochrome prints, things get more interesting. Various old photographic processes create images that are made up of very small particles of noble metals. Gold, silver, platinum (and other) processes create prints that, on archival quality papers, seem to be able to last for over a hundred years, perhaps much more if ambient conditions are controlled. And some of these old processes yield prints that are highly regarded aesthetically for their resolution and tonality. Simple carbon based inks are very stable - that's why you can still view old prints made from printing inks hundreds of years ago.

But the bottom line is this: Get your photos into open-standard-format digital files. Put those files on servers operated by reliable companies. Make some more temporal copies for your own use (magnetic and optical media) and keep those as working copies. Make prints from time to time, when you (or your descendants, or the future legal owners of the images) need them.

Let's hope that there will be humans around in a few hundred years who have leisure time (or work need) to enjoy your images.

Submitted by: Dion J. of Scotts Valley, CA