Steve asks: The question is -- Has anyone on this list, or otherwise, done any studies on the half life of photographic images recorded on various media? The "decay" or loss of any given image could be from a number of causes -- decay of the recording material, destruction due to damage from fire, water, etc., discard by owner, change in technologies, etc. Do the members on this list think that the half-live of photo images has significantly shortened, because of the shift to digital? What about different categories of images (professional vs consumer)? Should a criteria of technology be the lengthening, rather than the shortening of photo image half-life? Is there anyone working on this issue with a mathematical or statistical model? not that I know of, but half lives are readily determined for physical materials such as elements, anything that involves a statistical interpretation would have compounding error factors that would make such an interpretation vague at best.. basically - a guess These guys have millions of dollars at risk, and this is what they found when comparing film to digital: <http://www.nytimes.com/2007/12/23/business/media/23steal.html?_r=2&oref=sl ogin&ref=business&pagewanted=print> (http://tinyurl.com/lwuz2v ) As to the fad of going with the latest storage methods or migrating to new data storage media - the people who bought into HD over Blueray are probably regretting the cost and busy migrating everything to another media as we speak. A shame really, since HD had no DRM built in - but a no brainer really that the studios would go for the copy protected system over the flexible one. Blueray is probably heading for a dead end as well, so there may be a 'backward' 'upgrade' in years to come when that one finally dies.. For the time being magnetic (tape and HDD) still come up best. Longevity depends on storage more than anything else. Archiving is a storage process, not a method of manufacture - as the bits I posted not long back suggested regarding toning. Toning with suitable materials overcomes poor storage methods such as displaying a print, but a print deprived of oxygen will last much, much longer. The revelation that the old belief that poor processing was the reason prints degraded was a fallacy was telling. Many people in the archiving business have also failed to realise that many photos faded after time because they were DESIGNED to do so. I have here a photo manual that described in detail how the wedding proofs can be printed in such a way as to ensure they only last a short time, to stop the bride and groom simply keeping the proofs and not paying for prints. Of course an archivist stumbling across such prints wouldn't know that, and would be fighting an uphill battle saving such images, and would probably conclude from their experience that photographs don't last. they would be wrong, though such techniques were well known to photographers for a long time. As to colour prints, I also have prints from 1954 through to the current day. 1954. That is a 55yo colour print, and it looks great. I have many purple and orange prints from the 70's and 80's too, nasty faded things - when waterless wash systems were common in labs and prints were 'stabilized' with formaldehyde. Of course, we who knew about such processes knew these prints could be made to last longer by washing them in water - but many published archivists, the general population and indeed many photographers did not know this. Neither were many people of the mindset to experiment in trying different methods to prolong the life of such prints, subsequently they are doomed to fade. I posted a story some time back about an Australian auction site that competed locally with Ebay. Moderately successful, they had a crash and turned to their backup systems - which had been writing corrupted backups.. then they went to the offsite backup people they had been paying a grand amount to to run parallel backups weekly - and who had not. Last I heard it was all being seen to in court, but the fact remains that a thriving, prosperous auction site that had been doing all the right things is now gone. These guys had millions tied up in their digital world.. but it is now simply a memory. Anyone who is bored can get on the newsgroups some time and read the posts of people searching for old version of software. You'd think that software used by millions of people would be easy to find, but there is a LOT that has been lost. The idea of spreading the images around across a load of different web locations would be good in making sure the images survive *somewhere*, but then you'd have to ask yourself, how on earth would I find a particular image? Lost is as good as gone really. A few months back one of the Hospitals here in Aus had a power outage. Doctors had no access to patient records for a day or so. People in the hospital were being treated based on guesswork with no medical history available to the staff. Fortunately the information was all recovered (or so we are told) but for a period of time staff were working completely blind. This seems very irresponsible to me, and apparently it seems so to the good folks who are looking into it. A total dependence on digital has some serious flaws, the greatest being that in interpreter or interface is required to work between the human and the data. Anyone who speaks more than one language will understand the benefit of working without an interpreter :) This also leads to the storage matter - the interpreter must also be trustworthy - and if the computer is telling the operator that the data is fine and it's not, well.. CD's and DVD's have data correction built in as errors are inevitable - and a certain amount of errors is acceptable and correctable, but when one error too many creeps in (and these things DO degrade with time) then it's all over. Few people run error checking programs over their archive CD's or DVD's to see what the error rate is, fewer still check the disks regularly to see how much the disk errors increase over time. Really that is a specialised field all in it's own, and a job in it's own right. I doubt many people would dedicate the time to going over and over disks checking their state of decay and migrating the data when needed. I know I'm often seen to be a basher of digital, but it's not that at all - I see digital as a very good method of making data available to many with great ease. Used appropriately it is the most convenient method of distribution ever! it's just the longevity issues that concern me. karl
