Film photography has been superseded by digital photography.  A digital 
image file is superior in many ways.  The major reason is that the file 
will never degrade and can be copied without any loss.  In addition, the 
digital version has (1) color data associated with each pixel and (2) 
metadata about the image, should you add it to the file.

Storage is best done using a hard drive (HD).  Optical disks seem 
permanent, but they fail without warning and can fail with 3-5 years if 
not made in a prescribed manner.  I have an essay on this topic in the 
Jan'06 AICNews, and, there is a longer version, with online references 
to details of CDR and DVD-R use and storage at 
<http://aic.stanford.edu/sg/emg/library/pdf/vitale/2005-11-vitale-storage_image_files_long.pdf>.

A "single shot" digital photograph, from some DSLRs, is considered to be 
equivalent to, or better, than film.  The lens is the determining factor 
in most situations, if the DSLR has 11 MP or more.  I also have an 
exhaustive essay on this topic at 
<http://aic.stanford.edu/sg/emg/library/pdf/vitale/2006-01-vitale-digital_image_file_formats.pdf>. 


Scanning backs for view cameras (large format photography) and flatbed 
scanners offer the best solution for museum documentation of flat 
artifacts, including nearly flat artifacts, such as coins an medallions. 
  I prefer flatbed scanners for most situations because the far less 
expensive and can be used by almost anyone.  DSLRs all have a Bayer 
Pattern filter-set on the digital sensor (except Foevon type), which 
diminishes color resolution markedly, while the spatial resolution 
(pixels per inch) remains at the chip's resolution, through the lens 
being used.

Scanning devices have full color and spatial resolution, that is, there 
is a red, green and blue value for each pixel.  The lenses used with the 
device have fixed design and are optimized for the application.  Today's 
flatbed scanners have resolution up to 4800 ppi for around $500 (8.5" x 
11.75").  Tabloid size (12 x 18; $2000) flatbed's commonly have 2400 ppi 
resolution, but that far exceeds the reflective materials being scanned. 
  At 4800, ppi, the resolution is well beyond film, with the exception 
of B&W photography using T-max 100, shot through specific 50 or 85 mm 
Nikkor or Canon prime lenses.  The latter will have a resolution 
equivalent to 3800 ppi, and will be virtually equivalent to the flatbed, 
except the B&W film image will have no color information.  The details 
and proof of this assertion are all in PDF above.  I'm always pleased to 
discuss this in detail, should the need arise.

Film has a plastic base.  Most film is still on a cellulose acetate base 
(90% sold), unless one specifically seeks an Estar (polyester) based 
film; check film data sheets.  The acetate base will begin to show signs 
of deterioration in 30-50 years (Vinegar Syndrome) depending on type and 
storage.  Cold storage of film is the only way to slow this 
deterioration process, but cold storage unfortunately limits access.

B&W prints were thought to be stable for hundreds of years, however 
today's RC based papers have a usable life of about 20-30 years, some 
only 15 years.  Fiber based (FB) B&W photographic papers are rare today, 
and are showing themselves to be more vulnerable that we originally 
projected.  It seems that excellent FB photographic papers, from 
1960-Pr., have a new mode of deterioration.  They can become 
yellow-orange in the midtones, when exposed to high humidity for 
prolonged time, or are immersed in water for "treatment," of some sort. 
  The source of the problems is yet to be determined.  However, it seems 
to be associated with archival washing and/or hypo-clearing agents; a 
real shocker for an old archival-washing advocate.  This makes even FB, 
B&W photography, once though to be stable for 200-500 years, just as 
vulnerable as good color film and prints.  A real eye-opener.

Epson Ultrachrome and UltrachromeK3 pigmented inks, printed on the 
recommend Epson papers, using printers costing $150-6000, have a life of 
65-100 years on display (at 450 lux year round).   This is beginning to 
look better than both siver/dye based B&W and color (Fuji Crystal 
Archive, 65 yrs) output.

The digital file often has metadata associated with the image when it is 
made by the digital device.  In most image processing software, such as 
Adobe Photoshop, Apple Aperture and Adobe Lightroom (still in Beta), 
metadata such as keywords, artifact date & title and comments ( historic 
information, etc.) can be added to the image file, putting both image 
data and written documentation in one place.  The TIFF file format is 
one to use; see the second reference above for details.

Finally, this puts a great deal of emphasis on the storage medium. 
Optical disks such as CDR can have a life of 25-50 years if encoded just 
right, on specific products (only), while DVD-R/RW have only half that 
life, at best, because they use (only) less stable dye layers (why?), 
and the data density is about 6 time higher (740 MB vs 4.7 GB).  In 
addition, one will need an optical drive to read them, when are taken 
off the shelf for use.  There is no guarantee that these drives will be 
as common as they are now.  They will go the way of last yester-year's 
floppy drive, when a new technology comes along.

Today's HDs are far superior to even those made 5-10 years ago.  They 
use liquid bearings, rather than hard bearings, and their life (if they 
don't fail immediately) is projected to be 60,000 to 100,000 hours of 
continuous use 7-11 years (MTBF).  [Note that all digital storage must 
be backed up, period, no exception; you must back up optical as well.] 
I have used over 30 HD in the past 10 years and none has failed in 7 
years.  Sure, some of those HDs are not being used today because they 
were so small (2-6 GB), they were transferred to a larger HD (250 GB = 
$100, online, www.pricewatch.com) for use.  That is the data migration 
process.  We do it routinely because yesterday's HDs are too small and 
today's are so big.  In fact, I now backup my valuable old data CDs on a 
modern HD; about 450 disks (540 MB CDs) will fit on a $100, 250 GB HD.

Tim Vitale
Paper, Photographs &
Electronic Media Conservator
Digital Imaging & Facsimiles
Film Migration to Digital Domain
Preservation and Imaging Consulting
Preservation Associates
1500 Park Ave.
Suite 132
Emeryville, CA 94608

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510-594-8277
510-594-8799 fax

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