From: Jeff Kreines (email suppressed)
Date: Thu Jan 04 2007 - 23:57:42 PST
On Jan 5, 2007, at 12:15 AM, C Keefer wrote:
> If it's contemporary polyester-based stock, stored in an archival
> cold vault with proper temperature and humidity levels, perhaps 100
> years, perhaps more. That's assuming you're not pulling it in and
> out of the vault, making dozens of prints, etc. Fluctuation in
> temperatures and constant handling will increase the level of
> deterioration.
One mistaken assumption -- very few camera stocks are polyester-
based, because polyester film is very strong, and a camera jam can
actually break a claw. So with rare exceptions, camera originals are
still acetate, and subject to vinegar syndrome, shrinkage, and more.
>
> Re your questions below - When restoration is done on older color
> films, new preservation elements such as interpositives and
> internegatives are made. These are the valuable elements; new
> prints are for access, not necessarily a required part of
> preservation. The point of preservation is to protect the original
> negative (or master positive, or whatever is the best extant
> material) by making a preservation copy photochemically on stable
> stock, then storing it properly (and keeping and storing properly
> the original as well). Digital processes are not preservation
> (though some processes may be used to clean up problems in picture
> or track, like DRS, no-noise, etc.). Transfer and storage on any
> type of digital format is not preservation. It's storage, and a
> means to create access copies.
For 35mm material, photochemical preservation is great. However, I
assume Freya is talking about 16mm. There is a significant loss of
resolution with each generation of 16mm to 16mm contact printing, due
to printer slip (even in well-maintained printers). Stocks like
Kodachrome, and newer color negative stocks, have far more
information on a good camera original than you'll ever see in a
contact print. Things get worse with color negative stocks -- first
generation prints -- workprints, answer prints -- look great. But
(with the demise of CRI, long ago) with negative stocks, dupes mean
that release prints will be three generations (interpositive, dupe
negative, print) away from the original. (Color reversal stock saved
a generation, which made a big difference.)
16mm labs are disappearing, too -- while processing camera original
is not a problem, there's less and less demand for 16mm prints these
days, which means fewer labs, etc... a vicious circle.
>
> For older films, yes, the original negs are more prone to
> deterioration, as often they have been/are stored improperly and
> are on acetate-based stock (as opposed to today's polyester-based
> stock).
Again, most camera stocks are not polyester-based. Dupe stocks are,
and print stocks are.
>
> Making a preservation element (or 2) photochemically is proper
> preservation. Only then will there be an element for transfer to
> future digital formats over many generations, as needed for access.
> You cannot continually migrate digital files or videotapes to the
> next digital format, artifacts will be introduced at each
> migration. Just think about it - if you only had your films on 1"
> tape, then you reformat them to digibeta, and then the next format
> comes along, well, you're out of luck trying to reformat to HD.
> But if you have a negative (or even a print) to re-transfer to HD
> or BluRay or whatever, then you'll be fine. And so it goes over
> future generations, but you need that film element for transfer.
> Remember, the only playback medium that has lasted over 100 years
> is film. And ideally you want a preservation element sitting
> safely away in the cold vault, and another one for transfers &
> printing, but that's not always financially possible in A-G film,
> though we do strive for that as much as possible.
Digital storage is going to be the future of archiving, for good and/
or bad. Cost is the main reason. I agree completely that 35mm B&W
separation negatives on polyester stock is the best way to store a
film for future generations. Film is future-proof -- all you need is
a light bulb and a pair of rewinds to see what you have.
But you are making a straw-man case when discussing video. Video
copies of films are merely access copies, nothing more. While HD has
(according to the BBC's research) enough resolution to archive 16mm,
video is not the same thing as a digital scan. A digital scan has
greater bit depth and resolution than video, and is clonable. A 2K
scan, or even a 1600 x 1200 scan (greater res than HD for 4x3
material) has more resolution than HD, and more resolution than 16mm
camera originals ever will have (unless the laws of physics change).
The scans can easily be reformatted to any current or future video
standard, or output to film as required. But a film dupe may have
30% less resolution per contact-printed generation -- as well as a
build-up of grain and contrast in some cases -- losses that are hard
to overcome. (Optical printing is far less prone to registration
loss by printer slip.)
Of course, a wet-gate blow-up to 35mm is a great way to preserve 16mm
film, but it's not cheap.
That's the one thing that digital scans can make possible ---
scanning film at high resolution affordably. That makes it possible
to preserve films that might otherwise be lost.
>
> One last comment, storage on today's DVDs are probably the worst
> possible option. DVDs just don't last long at all, are easily
> scratched, etc., make sure you have your master on another format.
Ah, something we completely agree on.
For Freya, note that proper storage (low humidity, low temperature,
vented can) will preserve your color negative for many many years --
and improper storage will accelerate deterioration.
Jeff "pines for the days of many 16mm labs in every city" Kreines
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