Foibles & Failings of Contemporary Files
Scans - The first failing when scanning original images is not properly cleaning and preparing the image before scanning, since the scan will also record all the dirt and residue hiding the image.
Second, although the quality of scanning hardware is constantly improving, the technique and methods used to scan images are the catastrophic weak link! A typical "scan" fails to capture all of the subtle highlight and shadow detail available in the original image. It is these beautiful tonal nuances which make the old images so distinctive and captivating. And if this tonal detail is not totally captured by the original scan, it will never, never be recovered by any subsequent manipulation or enhancements! Guaranteed!
Third, There is a tendency to save black & white images as a "grayscale" rather than a color (RGB) file, to reduce the file size. This not only dramatically increases the potential for losing subtle image detail, it often completely eliminates any possibility of applying certain restoration techniques, which rely on color differentials!
Forth, scanning resolution is critical in preserving sufficient detail. Yet most image scans are done at insufficient resolutions which not only lose valuable detail but also destroy any potential for future quality restoration. Although an image may be subsequently interpolated, "upsampled" or otherwise increased in file size resolution, the original image's detail can never be recovered! Interpolation can only duplicate adjacent data. (A low resolution scan can NOT capture detail, Consequently interpolating a low rez scan merely duplicates lack of detail!)
Fifth, too many images are saved and stored in the potentially destructive JPEG file format! This "lossy" format discards needed image information data in order to compress the file size. If the image is ever saved more than once as a JPEG, the image quality is progressively an irrecoverable destroyed!
Sixth, saving properly scanned high resolution files in the preferred "TIFF" format, can require an enormous amount of storage (potentially getting as few as two or three files on a CD). These larger files also require more time to manipulate and save, as well as much more sophisticated computer and software systems.
Finally, although to the untrained eye, a typical "enhanced" scanned image may initially appear more attractive, in reality, it is forever irrevocably damaged! The image is forever lost! And so is your time and money!
CDs - More and more evidence indicates the digital CD (contrary to original speculations) has a shorter and shorter dependable life span. Some reports now caution a safe life span of less than a year! The stability of the digital information captured on a CD is also directly conditioned on the quality of the individual CD, as well as the hardware/software used to "burn" the disc. (Did you know a CD is like a regular photograph which can deteriorate when exposed to extensive light?)
Another flaw is most CDs are not verified once the data is "burned" onto the disc. It is not unusual to have a "bad sector" during the original "burn", and without verifying, corrupted files could go undetected, while the original data is purged, making any recovery impossible (even on the first day)!
Photographic Film - The first and most important challenge is to create an optimum image on the film. Properly cleaning and preparing the image before copying the original, since the copy neg will also record all the dirt and residue hiding the image.
The camera must be properly aligned to provide a square (rectilinear) reproduction and establish uniform light dispersion over a totally flat image. Special filters must be used to eliminate glare as well as the application of narrow spectrum attenuation to minimize or eliminate spots and stains. Exposure must be compensated not only for the various filtration methods but also for varying magnification rations and reciprocity failure. The choice of film also plays a vital factor in both the final image quality and sharpness, and as to the specific chemical choice and individual techniques used to optimize the film processing.
Practically all films now a days are processed by machines, precluding any possibility of achieving archival standards. There are a few , very few, labs who still hand process film, at a proportionately high costs. Although hand processing will achieve a higher image quality, without specific archival criteria compliance, there is no assurance the films will be preserved any longer than those done by a machine.
There are also black & white "chromagenic" films, which are actually color films (with only one color: black) and require "color" processing. These film can produce very high image quality, but have substantially less image permanence than even nominal grade black & white film with marginal processing.
Prints, Photographic or Digital - All of the weaknesses and short comings listed above apply to all printed images (except those specifically processed to meet ANSI archival standards). In addition there is also the problems of extra expenses and additional storage.