The other possibility is printing the images on paper in digital form. I recall a technique that would store digital data on paper that looked as if someone sprayed ink randomly at it.
Then of course, there is always antique "silver" film...
>I also wonder about polaroid images. Are the originals made 60 years ago still stable? <
The Polaroid photos my family took in the late 1950's - early 1960's are really deteriorating. Some are almost totally destroyed.
It's a shame, too. My dad loved his Polaroid, and used it a lot to record family events.
Color Polaroid images have a well known propensity for blue shift. I was one of those people who had to have the camera, and I got the folding one and spent lots of money on film packs. Great concept, I still have them, but to make them look good, I have to scan them in and Photoshop them.
My feeling is, the benefits of digital far outweigh the disadvantages, in my case at least. I am immersed in the digital end of things, I understand formats and migration.
I have my files backed up on two separate hard drives, I have them all archived and burned to DVD's which I have placed in my Safe Deposit Box at my bank.
But these are all good points people make. I will wait until the 3D Transparent Cubic storage units come out, because they will certainly last for a thousand years...:)