On Wed, Apr 30, 2008 at 1:34 PM, David Dyer-Bennet <dd-b@xxxxxxxx> wrote:
Fortunately this is not a common occurrence. It is also not an example of long term storage.
How do we know?
Magnetic or optical storage media also begins a cycle of degradation as soon as data is written. All storage media has a finite life. Lab tests to predict what that time frame is are done in labs under controlled conditions so we still only have ball park ideas since the media hasn't been around long long enough to verify the tests under 'normal' conditions.
Tru, this is just like taking a roll of stored film out of the freezer prior to using.
All archives, digital, film, paper, etc need 'competent management' to remain viable for very long times.
True. But as I saw a few years ago, someone was having difficulty getting data off of a 5.25" diskette but was able to print a sixty year old negative.
Some time ago I found a box of Kodachromes date stamped by Kodak as 1976 that I had lost. Many were dirty but the images, to the best of my abilities are like they were in '76. I haven't louped any of them but when projected after cleaning they still look good.
This is an interesting thread similar to Canon vs Nikon and Ford vs Chevy.
Bob
On Mon, April 28, 2008 00:34, Trevor Cunningham wrote:
> Here in lies a reason to prefer film over digital. Magnetic storage is
> far more unstable than sleeves and notebooks. Burned storage has a
> suprisingly limited shelf life, so we are learning. You can still play
> your cd's from the early 1980's, but the commerically produced materials
> are much higher quality than anything you can to make yourself.
> Indeed, digital is less expensive...but, then again, it's cheaper
Let's see; the first counter-case that comes to mind is the photographer
who died in the WTC attack. The film in his film camera was
unrecoverable, but all the images on the flash memory card were recovered.
Fortunately this is not a common occurrence. It is also not an example of long term storage.
There were also a collection of important negatives of the Kennedy family
in a safe-deposit vault under the building; you may have seen the book,
made from prints and contact sheets sitting around that photographer's
studio. If the data had been digital, there could have been more than one
copy, and it likely would have survived.
How do we know?
Film in sleeves and notebooks is degrading every single second it exists;
most especially color film. I've got works I shot myself with notable
color shifts and density loss.
Magnetic or optical storage media also begins a cycle of degradation as soon as data is written. All storage media has a finite life. Lab tests to predict what that time frame is are done in labs under controlled conditions so we still only have ball park ideas since the media hasn't been around long long enough to verify the tests under 'normal' conditions.
You have to go to controlled-humidity low-temperature storage to come
anywhere close to stopping film degradation. Mind you, that can be as
simple as a refrigerator and zip-lock bags, perhaps with silica dessicants
in them (I haven't tried to do this and haven't researched current
thoughts on best storage conditions). It also makes access slow and
somewhat painful, and risky (open the bag before it's warmed up and water
will condense all over your valuable negatives).
Tru, this is just like taking a roll of stored film out of the freezer prior to using.
I've been using Kodak Gold Ultima CD-Rs, and more recently MAM gold
archival DVDs. So far no disk I've tested has shown any significant
increase in error rates. Counting Kodak Photo CDs I got made, I have
examples going back to around 1994 that I keep checking up on. (The data
is also on multiple hard drives, and on more recent archive disks I
burned, but I like to check up on the older samples just for curiosity.)
These disks claim lives in the 200 year range -- obviously based on
accelerated testing rather than natural aging. In *that* timespan, I
don't expect DVD readers to be available any more, and I think file format
changes are pretty likely too.
Digital archives work wonderfully *when competently managed*. They are
*horrible* for long-term benign neglect. The ability to store multiple
copies in separate locations gives you the ability to protect against
problems that are intractable in analog (where copies are not only
expensive but *inferior*).
All archives, digital, film, paper, etc need 'competent management' to remain viable for very long times.
Analog media degrades constantly over time, but sometimes fairly slowly.
The right analog media do pretty well with long-term benign neglect.
So what I see here is that they have different characteristics, and so one
is better for some things, the other is better for others.
True. But as I saw a few years ago, someone was having difficulty getting data off of a 5.25" diskette but was able to print a sixty year old negative.
Some time ago I found a box of Kodachromes date stamped by Kodak as 1976 that I had lost. Many were dirty but the images, to the best of my abilities are like they were in '76. I haven't louped any of them but when projected after cleaning they still look good.
This is an interesting thread similar to Canon vs Nikon and Ford vs Chevy.
Bob
--
David Dyer-Bennet, dd-b@xxxxxxxx; http://dd-b.net/
Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
Photos: http://dd-b.net/photography/gallery/
Dragaera: http://dragaera.info
