How Long Will Your Pictures Last?
It all depends on you, your successors, and whether anyone else cares.
By Jason Schneider
Analog aficionados like me are excruciatingly aware that shooting pictures on film is considerably less convenient and a heck of a lot more expensive than shooting equivalent images with a digital camera. We do it because we love the leisurely pace of the traditional shooting experience, the distinctive esthetic qualities of images shot on film, the vintage rendition of our ancient cameras and lenses, and the astonished expressions on folks who watch us loading our cameras with strange metal cartridges or cylindrical rolls of paper-backed film. We’re also amused by the quizzical looks we get when we explain that we can’t show onlookers the photos of them we just shot on the LCD because there is no LCD!
However, there’s one aspect of shooting film where many film dinosaurs believe they have a technological ace in the hole. Their images can potentially last and be easily retrievable for hundreds, if not thousands of years because they’re captured on negatives, physical objects that can theoretically be preserved indefinitely if properly stored. In contrast, digital images are basically electronic data captured on media that are seemingly more ephemeral and subject to degradation. And even if by some miracle these data remain intact on a hard drive, archival CD, or some super memory card, 200 or 500 years hence, perhaps nobody will have the hardware, devices, or operating systems needed to display an ancient JPEG or TIFF, so they’ll essentially be lost forever. It’s a scenario that may be appealing to film fanatics, but as we’ll see, the facts and the limitations of preserving any kind of photographic images, are a lot more complicated.
The Niépce Heliograph, the earliest preserved photograph, an 8-hour exposure taken in 1826.
When it comes to preserving images on film, proper storage is critical to avoid chemical and physical deterioration of the images and loss of information. According to data from the RIT (Rochester Institute of Technology) Image Permanence Institute (IPI) there’s a direct relationship between the storage conditions (temperature, relative humidity and light level), and long-term image stability, and the differences can be startling. According to results published in the IPI Storage Guide for Acetate Film, a collection of triacetate-based film stored at 70°F and 40% relative humidity, will only remain in good condition for about 50 years. But the guide predicts that by lowering the temperature to 30°F at the same 40% relative humidity, fresh triacetate film in dark storage will last for 1000 years! In other words, the cost of maintaining an improved storage environment is directly proportional to the quantitative benefits measured in years of preservation. The study concludes that carefully controlled cold storage is the only viable option for enhancing the stability of film that has already shown signs of deterioration and the only way to maintain new or undamaged film in good condition for extended periods of time.
A picture worth saving: Earth shot by Lunar Orbiter from near lunar orbit taken on Kodak Bimat film, processed in space, scanned with a flying dot scanner, converted to an analog TV signal, and finally transferred to film.
All these stats and general principles apply to old cellulose nitrate-based films, current cellulose acetate and triacetate (TAC)- based films, and polyester (polyethylene terephthalate)-based films that were first introduced in 1955. The study notes that polyester based films may offer inherent advantages in terms of image stability and permanence, and they are recommended for making duplicates of any images intended for archival preservation. However, that is of little consequence for most film shooters since almost all current films, including black-and white emulsions, employ a triacetate base.
Portrait of Abraham Lincoln by Mathew Brady, February 1860, salted paper print.
The most economical way of preserving a collection of film images in good condition is cold storage at 30°F and 40% relative humidity. The chemical reactions driving the deterioration of acetate-based negatives are also autocatalytic, meaning that once the products of chemical degradation accumulate, and once deterioration starts, the process gains momentum. To prevent the build-up of gaseous by-products, negatives should be removed from sealed “air-tight” containers such as metal film canisters or plastic bags and installed in non-airtight boxes in well-ventilated spaces. All negative enclosures should pass the photographic activity test as prescribed by the American National Standards Institute (ANSI) Standard IT 9.2-1991. Before placing the negatives in enclosures, dust them with a wide, soft brush, and label the enclosures with a permanent archival ink meeting ANSI Standard IT 9.2-1991. Negatives should fit snugly, but not tightly into boxes that have reinforced seams, be acid-free with a high alpha-cellulose content, and meet ANSI Standard IT 9.2-1991. The boxes should have tight fitting “clamshell lids,” negatives of different formats should not be mixed in the same box, and films should be boxed separately by film type. Note: this is only a small portion of the IPI recommendations for archival storage of negatives and other types of images recorded on film, but it gives you some idea of the rigor and detail of the requirements.
Perspective of a Portal by Todd Gustavson, shot on a Nikon QV1000C electronic still video camera.
The cost of long-term film preservation? You don’t want to know!
The most economical way to preserve a collection of images on film in good condition for a century or longer is cold storage using frost-free freezer systems that regulate the temperature (by far the most important factor) and the humidity. Though duplication is a viable option, it is expensive, time-consuming, and not a perfect substitute for proper care of the originals. The bottom line: If your goal is to preserve your film images intact for generations or centuries, you must replicate what a museum like the George Eastman House in Rochester, New York has been doing for 75 years, and to arrange for that level of care and stewardship to continue in perpetuity! Significantly, the Eastman Museum’s top annual expense is not maintenance of its impressive facilities or paying its expert researchers and staff, but the cost of the energy required to maintain its display areas and dark storage facilities at optimum temperature and humidity levels. Not even considering that temperature regulated frost-free cold storage units require periodic maintenance and replacement, can you imagine the cost of just keeping the power on for 1000 years?! BTW, Current solar panels last for about 20 years.
Digital to the rescue? Sort of.
It may not please film fanatics who prize their negatives and slides as the ultimate physical representations of their precious photographs, but scanning is now generally considered the best way to preserve film images over extended time periods. Scanning to create digital files allows for the highest quality reproduction of the original negative, preserving the most detail and greatest color accuracy compared to simply making photographic dupes on film (which is also a lot more expensive and labor intensive). And scanning at hi-res to create digital files is now generally held by accredited conservators and major museums to be the best method to ensure long-term preservation of photographic images on film. Of course, preserving digital files in readable forms without compromising or losing any data presents its own unique challenges, which we’ll get into shortly.
Key advantages of scanning film to create digital files:
More detail from negatives:
Film negatives contain more image data than a printed photograph, so scanning directly from the negative provides a superior result.
Color accuracy:
High-quality scanners can accurately capture the colors from the film, especially when properly calibrated.
Digital longevity:
Once scanned, the image can be easily stored digitally and backed up for long-term preservation.
Shooting digital: Will your image files last, and will they be readable?
The digital JPEG, TIFF or DNG image files captured by your digital camera can potentially yield higher picture quality (sharpness and detail) and greater color accuracy than images shot on film, but digital storage media can lose data or even become unusable for a variety of reasons such as damaged spindle motors in hard drives. The flash memory found on solid state drives (SSDs) smartphones, USB flash drives, and memory cards (all types), can start to lose data around a year after their last use, depending on the storage temperature, and how much data was written on the device during its lifetime. Current “archival” disc-based media are only designed to last 50-100 years and most use a proprietary format.
The M-DISC is a DVD-based format claimed to retain digital data without loss or alteration for 1000 years, but writing to it and reading the data it contains requires special optical disc drives which may be difficult or impossible to find in 20 years, much less a millennium from now. In addition, the company behind it went bankrupt, highlighting another potential pitfall with all digital storage media. Linear Tape-Open (LTO), an open-format digital information storage technology created by HPE, IBM, and Seagate Technology requires periodic data migration since older LDO tapes cannot be read by newer LTO tape drives. RAID arrays (which store duplicate mirrored copies of all data on a drive) afford some protection against failure of a single hard drive, providing you don’t mix the drives of one array with those of another.
Common File formats compared
JPEG is the most popular image file format in use today because it meets the needs of the broadest spectrum of users and compatible with the widest variety of devices.
Advantages: Compressed file structure results in small file sizes, making them easy to transfer and store. Compatible with most browsers, software and apps. JPEGs can achieve high compression rates with little loss of visual image quality. JPEGs are ideal for web pages, email attachments, and archiving large photo collections.
Disadvantages: JPEGS use lossy compression, meaning that some image data is lost when the image is compressed. Repeated editing and saving JPEG images results in progressive loss of quality over time. JPEGs don’t support transparency, which is necessary for drawing templates logos and buttons, and are less suitable for working with text or monochrome graphics with clear boundaries.
TIFF is a lossless compression format widely used by professional and advanced photographers for storing and archiving images.
Advantages: Because TIFF is a lossless compression format it does not lose image quality if the dot per pixel value is modified. This capability makes TIFF images portable to almost every hardware and software, and allows them to be easily edited and modified, which is why they’re the de facto file type used by professional photographers and publishers who need to maintain quality while editing and storing images. You can compress TIFF images using virtually any file compression tool, archive multiple images in a single TIFF file, and TIFF is platform/hardware independent, facilitating resizing, transfer, editing and the overall flexibility of working with TIFFs.
Disadvantages: TIFF is a raster image file format made up of small bits so resizing can affect image quality. TIFF does not have a sophisticated security system, so users can set the security for a whole file, but not individual file components. The TIFF image format cannot imbed or attach other file types with it like, for example, PDF. TIFFs consume a lot of storage space even when compressed and take longer to open. PDFs are a better choice for Images requiring more sophisticated security and imbedding features, and for commercial printing.
DNG (Digital Negative Format) is a patented, lossless RAW image format developed by Adobe in 2004.
Advantages: DNG files are compatible with more software and devices than proprietary RAW files. DNG files are smaller than RAW files and help conserve disk space. DNG files have embedded metadata that makes them easier to manage and organize. DNG files are easier to edit because changes are written directly into the file. DNG is an open-access format so anyone can use it without restriction.
Disadvantages: DNG may not be able to capture every aspect of the proprietary format, especially if the manufacturer has incorporated unique features. Converting RAW files to DNG can take time and computer processing power. Some software may not fully support all the features and metadata contained within a DNG file. It is possible to lose camera brand specific data (e.g. color balance) when converting to a DNG.
Kish stone tablet section of c.3,500 BCE is the oldest known example of human writing, but it hasn't been deciphered.
Data retrieval is a problem that is literally thousands of years old. The earliest preserved example of written text is the Kish Tablet of c.3500 BCE found in the ancient city of Kish in modern day Iraq. A small limestone tablet clearly inscribed in pre-cuneiform pictographic writing. It has yet to be deciphered—indeed, it’s not even certain that it corresponds to any language that was spoken at the time! The Rosetta Stone, discovered in 1799 by French soldiers building fortifications in the Egyptian town of Rosetta (now Rashid) was much more enlightening. Inscribed with three versions of a decree issued in 196 BCE by King Ptolemy V Epiphanes, the top register (excerpt) is in Egyptian hieroglyphics, the middle one is written in Demotic, a cursive form of hieroglyphics, and the bottom one is in Ancient Greek, using the Greek alphabet. The presence of Greek convinced the French soldiers that they had found something significant, and they turned it over to Egyptologists who realized that the Greek text repeated the hieroglyphic texts and used the tablet to decipher the hieroglyphics. The lesson for those striving to preserve digital files for millennia: include keys to unlocking the data, and indelibly mark the storage device with a detailed description of the contents. Modern examples abound. Just try opening a WordPerfect document in a current version of Windows or recovering data from and old floppy disk and you’ll soon see that preserving the bits is not necessarily the hardest part—it’s determining what they mean!
To this end, Mahadev Satyanarayanan (“Satya”) at Carnegie Mellon University began to develop a platform designed to catalog and record both the digital objects (e.g. image files) we create and descriptions of the software and hardware that make them interpretable. Known as The Olive Archive, Satya’s platform is designed to address one of the trickiest problems, how to preserveexecutable files. Rather than having to preserve every single piece of hardware in working condition, a daunting and nearly impossible task, Staya’s goal is to create “virtual machines,” maps or descriptions of the hardware, that will allow old programs to be recreated using new software. Emulating past hardware isn’t a new idea, but the idea of building a repository capable of opening and executing any digital object is a massive undertaking.
Identifiers: How to know what you’re looking for.
Organization is one of the main pillars of image preservation because merely having information is of little value if you can’t find what you’re looking for. To preserve digital content and manage its collection effectively it’s essential to use assigned identifiers and accurate descriptive metadata. An identifier is a unique label used to reference an object or record (digital file), usually given as a string of numbers and letters. It’s a crucial part of the metadata included in a database record or inventory, used in tandem with other descriptive metadata to differentiate objects (files) and their various iterations. Descriptive metadata refers to information about a file’s content such as title, creator, subject, date, etc. that helps to minimize the risk of a digital object becoming inaccessible. Implementing a filename protocol such as 8.3 filename or Warez standard naming is essential to consistent and efficient discovery of stored objects (files), especially with digitized files of analog media such as film images. It will also ensure compatibility with other systems and facilitate the periodic migration of data, another key element of long-term digital data preservation. However, filenames are not good for semantic (descriptive) identification because they are non-permanent labels for a specific location in a system and can be modified without affecting the bit-level profile of a digital file.
Essential elements necessary for long-term digital file preservation
Integrity: Data integrity refers to the assurance e that the data is “complete and unaltered in all essential respects” and a program designed to maintain integrity aims to ensure that data is recorded exactly as intended and will be the same when subsequently retrieved, Unintentional changes are to be avoided, and strategies to detect such changes should be implemented. If preservation necessitates modifications to content or metadata, the procedures used should be responsibly developed and well documented, and integrity-checked versions of the originals should be retained. The integrity of a record can be maintained through bit-level preservation, fixity checking, and capturing a full audit trail of all preservation actions performed on the record.
Fixity: This is the property of a digital file being fixed or unchanged. File fixity checking is the process of validating that a file has not been changed or altered from a previous state, a procedure often enabled by the creation, validation, and management of checksums, values that represent the bits in a data set, and are the calculated using a function that depends on the content of the object or file. The checksum is then stored or transmitted with the data, and when the data is received the checksum is recalculated and compared to the original checksum. If the checksums don’t match the data may have been tampered with or infected with malware.
Sustainability: This encompasses a constellation of issues and concepts that contribute to the longevity of digital information that focus on building a flexible infrastructure emphasizing interoperability, ongoing maintenance, and continuous development. It incorporates activities in the present that facilitate access and availability into the future, a process analogous to the successful centuries-old community upkeep of ancient relics. Examples: the Uffington White Horse, a 360-foot-long hill figure of a horse formed from deep trenches dug into a hillside in Uffington, Oxfordshire, then filled with white crushed chalk sometime between 1380 and 550 BCE. The Ise Shrine, a Shinto temple complex in Japan’s Mie prefecture dating back to about 4 BCE.
Uffington White Horse from the air. British locals have been dedicated to preserving this ancient relic for centuries, a tactic we need to emulate!
Recorded media such as film or digital files can become corrupted due to physical and chemical degradation caused by lack of maintenance and/or inadequate storage conditions. However, images originally captured or replicated and stored as digital files can also become unreadable when access to digital content requires “external dependencies” that are no longer manufactured, maintained, or supported. These can include hardware, software, or physical carriers. A good example is DLT tape, a magnetic tape data storage technology that was originally developed in 1984, later imprved as Super DLT (SDLT), and phased out and shifted to LTO tape in 2007. While data recovery services for DLT and SDLT tapes are still available, they should be converted to a more viable format as soon as possible to ensure future readability and high-level information retention.
Bottom line: Whatever file formats archiving institutions choose, experience suggests they should be open, standardized, non-proprietary, and well-established to enable long-term archival use. Among the deciding factors should be: disclosure transparency, widespread adoption, self-documentation capability, and the impact of patents and technical protection mechanisms. Additional considerations for selecting sustainable file formats include format longevity and maturity, adaptation by relevant professional communities, incorporated information standards, and long-term accessibility of any viewing software. For example, the Smithsonian Institution Archives considers uncompressed TIFFs to be “a good preservation format for born-digital and digitized still images, because of its maturity, wide adaptation in various communities, and thorough documentation.” Whatever other advantages they may offer, formats unique to one software vendor are more likely to become obsolete and difficult to decipher than widely used formats like JPEG, even though the latter enables significant variations in color palette, contrast, etc. depending on brand of camera used to capture the file.
Wait, there’s more!
In addition to everything noted above, there are many other parameters that must be taken into consideration by museums databases and other organizations whose mission is preserving and providing access to digital images over extended times.
Significant Properties refer to those essential attributes of a “digital object” which affect its appearance, behavior, quality and usability, aspects that must be preserved over time to remain accessible and meaningful. In short, understanding and defining Significant Properties is part if the process of deciding which properties are worth preserving, developing preservation metadata, the assessment of preservation strategies, and developing common standards across the preservation community. Authenticity, whether in the analog or digital domain, is defined as the trustworthiness of a record, that it is what it purports to be, and is free of tampering.
Authenticity is not the same thing as accuracy—it’s more like a chain of custody. In other words, an inaccurate record may be acquired and its authenticity as an inaccurate record may be preserved so long as it has not been altered while in the archive’s custody! Most digital preservation efforts are directed toward enabling good decision making in the future. Should an archive decide on a particular strategy, the content and associated metadata must be available in unaltered form to allow good decision making by the controlling party.
The key enablers for digital preservation include the preservation metadata (technical information about the file), information about its components and its computing environment, information that documents the preservation process, and the underlying rights basis. All this allows the organizations or individual researchers to understand the chain of custody—the preservation history of the data over time. Preservation Metadata: Implementation Strategies (PREMIS) is the de facto standard that defines the implementable core preservation metadata used by most repositories and institutions, and includes guidelines and recommendations for its usage, and a common vocabulary of clearly defined terms.
The challenges of long-term preservation of digital information have been recognized by the archival community for years, resulting in actions, policies, and reports issued by the following: The Research Libraries Group (RLG), Commission on Preservation and Access (CPA), Open Archival Information System (OASIS), the Online Computer Library Center (OCLC) and the Trusted Digital Repository (TDR). Other approaches to digital object preservation include the creation of Trustworthy Digital Objects (TDOs) that can verify their own content validity and authenticity to future users by incorporating a record of their change history, and the International Research on Permanent Authentic Records in Electronic Systems (InterPARES), which has developed guidelines, action plans, and training programs on long-term
preservation for small and medium-sized organizations.
Can you save everything, and if not, how do you choose?
Traditionally, societies have preserved their heritage on long-lasting materials including stone, ceramic, non-oxidizing metals, etc. and more perishable but still relatively archival materials such as vellum, parchment, bamboo, and paper. Unlike traditional material such as books, scrolls, or analog photographs where the user has unmediated access to the content, digital information and image files always need a software environment to render it—and these environments keep evolving at a rapid pace, threatening the continuity of access. The previously mentioned protocols are all, in their own way, designed to address these issues, but there are other “existential” considerations.
When you consider the immense volume of digital data, including all manner of images, texts, and raw information, created every day, does it make sense to save it all, and if not, who decides what to keep? For many photographers the repository of last resort is “the Cloud”, but which clouds will endure? Will the Apple Cloud still be around in 500 or 1000 years? Will all the information in all current cloud storage sites be merged into a Mega-Cloud of the future and stored in perpetuity, and in continually updated form to remain readable? Does it even make sense to preserve every bit of the undifferentiated digital minutiae created by a society for “eternity,” or only to preserve the “important” stuff? And then who gets to decide what’s important?
Clearly if you want to assure that your images, both analog and digital, are preserved for, say, the next 1000 years and not consigned to the oblivion of what amounts to an immense scrapheap, you must take personal custody of them and arrange for their continuing care going forward. Your analog images must be physically preserved in controlled cold storage for as long as possible and converted “perfectly” with as little loss as possible, to TIFF or DNG (Digital Negative) files or whatever superior uncompressed file system of the future takes their place. They must be refreshed or duplicated at regular intervals to prevent degradation of information, and to assure they remain in a format that’s readable using current technology. What all this entails is a system of ongoing stewardship, which is neither cheap, easy, or guaranteed once you are gone. It also entails the continuity of human civilization, which has so far lasted more-or-less intact for “only” about !0-12-thousand years and is by no means guaranteed to do so for the next millennium, especially given the way things seem to be going. Perhaps that’s why NASA sent a “Golden Record” documenting human civilization into outer space aboard the Voyager in the hope it might someday be discovered by a superior—or luckier—extraterrestrial species.
The motivation to preserve our photographs (and other creative output) is clearly implied in the ancient Roman dictum, Ars Longa Vita Brevis, roughly translated as “Life is short (but) Art endures.” In essence, it because we are mortal that we want to leave something physical behind, a memento that expresses our life, our being, our experiences, and our perceptions. In fact, all we can really do is stall for time, because nothing, including the earth, the sun, the solar system and maybe even the universe, lasts forever.
In the immortal words of Emily Dickinson (No. 936, c. 1863):
This Dust, and its Feature—
Accredited—Today—
Will in a second Future—
Cease to identify—
It all depends on you, your successors, and whether anyone else cares.
By Jason Schneider
Analog aficionados like me are excruciatingly aware that shooting pictures on film is considerably less convenient and a heck of a lot more expensive than shooting equivalent images with a digital camera. We do it because we love the leisurely pace of the traditional shooting experience, the distinctive esthetic qualities of images shot on film, the vintage rendition of our ancient cameras and lenses, and the astonished expressions on folks who watch us loading our cameras with strange metal cartridges or cylindrical rolls of paper-backed film. We’re also amused by the quizzical looks we get when we explain that we can’t show onlookers the photos of them we just shot on the LCD because there is no LCD!
However, there’s one aspect of shooting film where many film dinosaurs believe they have a technological ace in the hole. Their images can potentially last and be easily retrievable for hundreds, if not thousands of years because they’re captured on negatives, physical objects that can theoretically be preserved indefinitely if properly stored. In contrast, digital images are basically electronic data captured on media that are seemingly more ephemeral and subject to degradation. And even if by some miracle these data remain intact on a hard drive, archival CD, or some super memory card, 200 or 500 years hence, perhaps nobody will have the hardware, devices, or operating systems needed to display an ancient JPEG or TIFF, so they’ll essentially be lost forever. It’s a scenario that may be appealing to film fanatics, but as we’ll see, the facts and the limitations of preserving any kind of photographic images, are a lot more complicated.
The Niépce Heliograph, the earliest preserved photograph, an 8-hour exposure taken in 1826.
When it comes to preserving images on film, proper storage is critical to avoid chemical and physical deterioration of the images and loss of information. According to data from the RIT (Rochester Institute of Technology) Image Permanence Institute (IPI) there’s a direct relationship between the storage conditions (temperature, relative humidity and light level), and long-term image stability, and the differences can be startling. According to results published in the IPI Storage Guide for Acetate Film, a collection of triacetate-based film stored at 70°F and 40% relative humidity, will only remain in good condition for about 50 years. But the guide predicts that by lowering the temperature to 30°F at the same 40% relative humidity, fresh triacetate film in dark storage will last for 1000 years! In other words, the cost of maintaining an improved storage environment is directly proportional to the quantitative benefits measured in years of preservation. The study concludes that carefully controlled cold storage is the only viable option for enhancing the stability of film that has already shown signs of deterioration and the only way to maintain new or undamaged film in good condition for extended periods of time.
A picture worth saving: Earth shot by Lunar Orbiter from near lunar orbit taken on Kodak Bimat film, processed in space, scanned with a flying dot scanner, converted to an analog TV signal, and finally transferred to film.
All these stats and general principles apply to old cellulose nitrate-based films, current cellulose acetate and triacetate (TAC)- based films, and polyester (polyethylene terephthalate)-based films that were first introduced in 1955. The study notes that polyester based films may offer inherent advantages in terms of image stability and permanence, and they are recommended for making duplicates of any images intended for archival preservation. However, that is of little consequence for most film shooters since almost all current films, including black-and white emulsions, employ a triacetate base.
Portrait of Abraham Lincoln by Mathew Brady, February 1860, salted paper print.
The most economical way of preserving a collection of film images in good condition is cold storage at 30°F and 40% relative humidity. The chemical reactions driving the deterioration of acetate-based negatives are also autocatalytic, meaning that once the products of chemical degradation accumulate, and once deterioration starts, the process gains momentum. To prevent the build-up of gaseous by-products, negatives should be removed from sealed “air-tight” containers such as metal film canisters or plastic bags and installed in non-airtight boxes in well-ventilated spaces. All negative enclosures should pass the photographic activity test as prescribed by the American National Standards Institute (ANSI) Standard IT 9.2-1991. Before placing the negatives in enclosures, dust them with a wide, soft brush, and label the enclosures with a permanent archival ink meeting ANSI Standard IT 9.2-1991. Negatives should fit snugly, but not tightly into boxes that have reinforced seams, be acid-free with a high alpha-cellulose content, and meet ANSI Standard IT 9.2-1991. The boxes should have tight fitting “clamshell lids,” negatives of different formats should not be mixed in the same box, and films should be boxed separately by film type. Note: this is only a small portion of the IPI recommendations for archival storage of negatives and other types of images recorded on film, but it gives you some idea of the rigor and detail of the requirements.
Perspective of a Portal by Todd Gustavson, shot on a Nikon QV1000C electronic still video camera.
The cost of long-term film preservation? You don’t want to know!
The most economical way to preserve a collection of images on film in good condition for a century or longer is cold storage using frost-free freezer systems that regulate the temperature (by far the most important factor) and the humidity. Though duplication is a viable option, it is expensive, time-consuming, and not a perfect substitute for proper care of the originals. The bottom line: If your goal is to preserve your film images intact for generations or centuries, you must replicate what a museum like the George Eastman House in Rochester, New York has been doing for 75 years, and to arrange for that level of care and stewardship to continue in perpetuity! Significantly, the Eastman Museum’s top annual expense is not maintenance of its impressive facilities or paying its expert researchers and staff, but the cost of the energy required to maintain its display areas and dark storage facilities at optimum temperature and humidity levels. Not even considering that temperature regulated frost-free cold storage units require periodic maintenance and replacement, can you imagine the cost of just keeping the power on for 1000 years?! BTW, Current solar panels last for about 20 years.
Digital to the rescue? Sort of.
It may not please film fanatics who prize their negatives and slides as the ultimate physical representations of their precious photographs, but scanning is now generally considered the best way to preserve film images over extended time periods. Scanning to create digital files allows for the highest quality reproduction of the original negative, preserving the most detail and greatest color accuracy compared to simply making photographic dupes on film (which is also a lot more expensive and labor intensive). And scanning at hi-res to create digital files is now generally held by accredited conservators and major museums to be the best method to ensure long-term preservation of photographic images on film. Of course, preserving digital files in readable forms without compromising or losing any data presents its own unique challenges, which we’ll get into shortly.
Key advantages of scanning film to create digital files:
More detail from negatives:
Film negatives contain more image data than a printed photograph, so scanning directly from the negative provides a superior result.
Color accuracy:
High-quality scanners can accurately capture the colors from the film, especially when properly calibrated.
Digital longevity:
Once scanned, the image can be easily stored digitally and backed up for long-term preservation.
Shooting digital: Will your image files last, and will they be readable?
The digital JPEG, TIFF or DNG image files captured by your digital camera can potentially yield higher picture quality (sharpness and detail) and greater color accuracy than images shot on film, but digital storage media can lose data or even become unusable for a variety of reasons such as damaged spindle motors in hard drives. The flash memory found on solid state drives (SSDs) smartphones, USB flash drives, and memory cards (all types), can start to lose data around a year after their last use, depending on the storage temperature, and how much data was written on the device during its lifetime. Current “archival” disc-based media are only designed to last 50-100 years and most use a proprietary format.
The M-DISC is a DVD-based format claimed to retain digital data without loss or alteration for 1000 years, but writing to it and reading the data it contains requires special optical disc drives which may be difficult or impossible to find in 20 years, much less a millennium from now. In addition, the company behind it went bankrupt, highlighting another potential pitfall with all digital storage media. Linear Tape-Open (LTO), an open-format digital information storage technology created by HPE, IBM, and Seagate Technology requires periodic data migration since older LDO tapes cannot be read by newer LTO tape drives. RAID arrays (which store duplicate mirrored copies of all data on a drive) afford some protection against failure of a single hard drive, providing you don’t mix the drives of one array with those of another.
Common File formats compared
JPEG is the most popular image file format in use today because it meets the needs of the broadest spectrum of users and compatible with the widest variety of devices.
Advantages: Compressed file structure results in small file sizes, making them easy to transfer and store. Compatible with most browsers, software and apps. JPEGs can achieve high compression rates with little loss of visual image quality. JPEGs are ideal for web pages, email attachments, and archiving large photo collections.
Disadvantages: JPEGS use lossy compression, meaning that some image data is lost when the image is compressed. Repeated editing and saving JPEG images results in progressive loss of quality over time. JPEGs don’t support transparency, which is necessary for drawing templates logos and buttons, and are less suitable for working with text or monochrome graphics with clear boundaries.
TIFF is a lossless compression format widely used by professional and advanced photographers for storing and archiving images.
Advantages: Because TIFF is a lossless compression format it does not lose image quality if the dot per pixel value is modified. This capability makes TIFF images portable to almost every hardware and software, and allows them to be easily edited and modified, which is why they’re the de facto file type used by professional photographers and publishers who need to maintain quality while editing and storing images. You can compress TIFF images using virtually any file compression tool, archive multiple images in a single TIFF file, and TIFF is platform/hardware independent, facilitating resizing, transfer, editing and the overall flexibility of working with TIFFs.
Disadvantages: TIFF is a raster image file format made up of small bits so resizing can affect image quality. TIFF does not have a sophisticated security system, so users can set the security for a whole file, but not individual file components. The TIFF image format cannot imbed or attach other file types with it like, for example, PDF. TIFFs consume a lot of storage space even when compressed and take longer to open. PDFs are a better choice for Images requiring more sophisticated security and imbedding features, and for commercial printing.
DNG (Digital Negative Format) is a patented, lossless RAW image format developed by Adobe in 2004.
Advantages: DNG files are compatible with more software and devices than proprietary RAW files. DNG files are smaller than RAW files and help conserve disk space. DNG files have embedded metadata that makes them easier to manage and organize. DNG files are easier to edit because changes are written directly into the file. DNG is an open-access format so anyone can use it without restriction.
Disadvantages: DNG may not be able to capture every aspect of the proprietary format, especially if the manufacturer has incorporated unique features. Converting RAW files to DNG can take time and computer processing power. Some software may not fully support all the features and metadata contained within a DNG file. It is possible to lose camera brand specific data (e.g. color balance) when converting to a DNG.
Kish stone tablet section of c.3,500 BCE is the oldest known example of human writing, but it hasn't been deciphered.
Data retrieval is a problem that is literally thousands of years old. The earliest preserved example of written text is the Kish Tablet of c.3500 BCE found in the ancient city of Kish in modern day Iraq. A small limestone tablet clearly inscribed in pre-cuneiform pictographic writing. It has yet to be deciphered—indeed, it’s not even certain that it corresponds to any language that was spoken at the time! The Rosetta Stone, discovered in 1799 by French soldiers building fortifications in the Egyptian town of Rosetta (now Rashid) was much more enlightening. Inscribed with three versions of a decree issued in 196 BCE by King Ptolemy V Epiphanes, the top register (excerpt) is in Egyptian hieroglyphics, the middle one is written in Demotic, a cursive form of hieroglyphics, and the bottom one is in Ancient Greek, using the Greek alphabet. The presence of Greek convinced the French soldiers that they had found something significant, and they turned it over to Egyptologists who realized that the Greek text repeated the hieroglyphic texts and used the tablet to decipher the hieroglyphics. The lesson for those striving to preserve digital files for millennia: include keys to unlocking the data, and indelibly mark the storage device with a detailed description of the contents. Modern examples abound. Just try opening a WordPerfect document in a current version of Windows or recovering data from and old floppy disk and you’ll soon see that preserving the bits is not necessarily the hardest part—it’s determining what they mean!
To this end, Mahadev Satyanarayanan (“Satya”) at Carnegie Mellon University began to develop a platform designed to catalog and record both the digital objects (e.g. image files) we create and descriptions of the software and hardware that make them interpretable. Known as The Olive Archive, Satya’s platform is designed to address one of the trickiest problems, how to preserveexecutable files. Rather than having to preserve every single piece of hardware in working condition, a daunting and nearly impossible task, Staya’s goal is to create “virtual machines,” maps or descriptions of the hardware, that will allow old programs to be recreated using new software. Emulating past hardware isn’t a new idea, but the idea of building a repository capable of opening and executing any digital object is a massive undertaking.
Identifiers: How to know what you’re looking for.
Organization is one of the main pillars of image preservation because merely having information is of little value if you can’t find what you’re looking for. To preserve digital content and manage its collection effectively it’s essential to use assigned identifiers and accurate descriptive metadata. An identifier is a unique label used to reference an object or record (digital file), usually given as a string of numbers and letters. It’s a crucial part of the metadata included in a database record or inventory, used in tandem with other descriptive metadata to differentiate objects (files) and their various iterations. Descriptive metadata refers to information about a file’s content such as title, creator, subject, date, etc. that helps to minimize the risk of a digital object becoming inaccessible. Implementing a filename protocol such as 8.3 filename or Warez standard naming is essential to consistent and efficient discovery of stored objects (files), especially with digitized files of analog media such as film images. It will also ensure compatibility with other systems and facilitate the periodic migration of data, another key element of long-term digital data preservation. However, filenames are not good for semantic (descriptive) identification because they are non-permanent labels for a specific location in a system and can be modified without affecting the bit-level profile of a digital file.
Essential elements necessary for long-term digital file preservation
Integrity: Data integrity refers to the assurance e that the data is “complete and unaltered in all essential respects” and a program designed to maintain integrity aims to ensure that data is recorded exactly as intended and will be the same when subsequently retrieved, Unintentional changes are to be avoided, and strategies to detect such changes should be implemented. If preservation necessitates modifications to content or metadata, the procedures used should be responsibly developed and well documented, and integrity-checked versions of the originals should be retained. The integrity of a record can be maintained through bit-level preservation, fixity checking, and capturing a full audit trail of all preservation actions performed on the record.
Fixity: This is the property of a digital file being fixed or unchanged. File fixity checking is the process of validating that a file has not been changed or altered from a previous state, a procedure often enabled by the creation, validation, and management of checksums, values that represent the bits in a data set, and are the calculated using a function that depends on the content of the object or file. The checksum is then stored or transmitted with the data, and when the data is received the checksum is recalculated and compared to the original checksum. If the checksums don’t match the data may have been tampered with or infected with malware.
Sustainability: This encompasses a constellation of issues and concepts that contribute to the longevity of digital information that focus on building a flexible infrastructure emphasizing interoperability, ongoing maintenance, and continuous development. It incorporates activities in the present that facilitate access and availability into the future, a process analogous to the successful centuries-old community upkeep of ancient relics. Examples: the Uffington White Horse, a 360-foot-long hill figure of a horse formed from deep trenches dug into a hillside in Uffington, Oxfordshire, then filled with white crushed chalk sometime between 1380 and 550 BCE. The Ise Shrine, a Shinto temple complex in Japan’s Mie prefecture dating back to about 4 BCE.
Uffington White Horse from the air. British locals have been dedicated to preserving this ancient relic for centuries, a tactic we need to emulate!
Recorded media such as film or digital files can become corrupted due to physical and chemical degradation caused by lack of maintenance and/or inadequate storage conditions. However, images originally captured or replicated and stored as digital files can also become unreadable when access to digital content requires “external dependencies” that are no longer manufactured, maintained, or supported. These can include hardware, software, or physical carriers. A good example is DLT tape, a magnetic tape data storage technology that was originally developed in 1984, later imprved as Super DLT (SDLT), and phased out and shifted to LTO tape in 2007. While data recovery services for DLT and SDLT tapes are still available, they should be converted to a more viable format as soon as possible to ensure future readability and high-level information retention.
Bottom line: Whatever file formats archiving institutions choose, experience suggests they should be open, standardized, non-proprietary, and well-established to enable long-term archival use. Among the deciding factors should be: disclosure transparency, widespread adoption, self-documentation capability, and the impact of patents and technical protection mechanisms. Additional considerations for selecting sustainable file formats include format longevity and maturity, adaptation by relevant professional communities, incorporated information standards, and long-term accessibility of any viewing software. For example, the Smithsonian Institution Archives considers uncompressed TIFFs to be “a good preservation format for born-digital and digitized still images, because of its maturity, wide adaptation in various communities, and thorough documentation.” Whatever other advantages they may offer, formats unique to one software vendor are more likely to become obsolete and difficult to decipher than widely used formats like JPEG, even though the latter enables significant variations in color palette, contrast, etc. depending on brand of camera used to capture the file.
Wait, there’s more!
In addition to everything noted above, there are many other parameters that must be taken into consideration by museums databases and other organizations whose mission is preserving and providing access to digital images over extended times.
Significant Properties refer to those essential attributes of a “digital object” which affect its appearance, behavior, quality and usability, aspects that must be preserved over time to remain accessible and meaningful. In short, understanding and defining Significant Properties is part if the process of deciding which properties are worth preserving, developing preservation metadata, the assessment of preservation strategies, and developing common standards across the preservation community. Authenticity, whether in the analog or digital domain, is defined as the trustworthiness of a record, that it is what it purports to be, and is free of tampering.
Authenticity is not the same thing as accuracy—it’s more like a chain of custody. In other words, an inaccurate record may be acquired and its authenticity as an inaccurate record may be preserved so long as it has not been altered while in the archive’s custody! Most digital preservation efforts are directed toward enabling good decision making in the future. Should an archive decide on a particular strategy, the content and associated metadata must be available in unaltered form to allow good decision making by the controlling party.
The key enablers for digital preservation include the preservation metadata (technical information about the file), information about its components and its computing environment, information that documents the preservation process, and the underlying rights basis. All this allows the organizations or individual researchers to understand the chain of custody—the preservation history of the data over time. Preservation Metadata: Implementation Strategies (PREMIS) is the de facto standard that defines the implementable core preservation metadata used by most repositories and institutions, and includes guidelines and recommendations for its usage, and a common vocabulary of clearly defined terms.
The challenges of long-term preservation of digital information have been recognized by the archival community for years, resulting in actions, policies, and reports issued by the following: The Research Libraries Group (RLG), Commission on Preservation and Access (CPA), Open Archival Information System (OASIS), the Online Computer Library Center (OCLC) and the Trusted Digital Repository (TDR). Other approaches to digital object preservation include the creation of Trustworthy Digital Objects (TDOs) that can verify their own content validity and authenticity to future users by incorporating a record of their change history, and the International Research on Permanent Authentic Records in Electronic Systems (InterPARES), which has developed guidelines, action plans, and training programs on long-term
preservation for small and medium-sized organizations.
Can you save everything, and if not, how do you choose?
Traditionally, societies have preserved their heritage on long-lasting materials including stone, ceramic, non-oxidizing metals, etc. and more perishable but still relatively archival materials such as vellum, parchment, bamboo, and paper. Unlike traditional material such as books, scrolls, or analog photographs where the user has unmediated access to the content, digital information and image files always need a software environment to render it—and these environments keep evolving at a rapid pace, threatening the continuity of access. The previously mentioned protocols are all, in their own way, designed to address these issues, but there are other “existential” considerations.
When you consider the immense volume of digital data, including all manner of images, texts, and raw information, created every day, does it make sense to save it all, and if not, who decides what to keep? For many photographers the repository of last resort is “the Cloud”, but which clouds will endure? Will the Apple Cloud still be around in 500 or 1000 years? Will all the information in all current cloud storage sites be merged into a Mega-Cloud of the future and stored in perpetuity, and in continually updated form to remain readable? Does it even make sense to preserve every bit of the undifferentiated digital minutiae created by a society for “eternity,” or only to preserve the “important” stuff? And then who gets to decide what’s important?
Clearly if you want to assure that your images, both analog and digital, are preserved for, say, the next 1000 years and not consigned to the oblivion of what amounts to an immense scrapheap, you must take personal custody of them and arrange for their continuing care going forward. Your analog images must be physically preserved in controlled cold storage for as long as possible and converted “perfectly” with as little loss as possible, to TIFF or DNG (Digital Negative) files or whatever superior uncompressed file system of the future takes their place. They must be refreshed or duplicated at regular intervals to prevent degradation of information, and to assure they remain in a format that’s readable using current technology. What all this entails is a system of ongoing stewardship, which is neither cheap, easy, or guaranteed once you are gone. It also entails the continuity of human civilization, which has so far lasted more-or-less intact for “only” about !0-12-thousand years and is by no means guaranteed to do so for the next millennium, especially given the way things seem to be going. Perhaps that’s why NASA sent a “Golden Record” documenting human civilization into outer space aboard the Voyager in the hope it might someday be discovered by a superior—or luckier—extraterrestrial species.
The motivation to preserve our photographs (and other creative output) is clearly implied in the ancient Roman dictum, Ars Longa Vita Brevis, roughly translated as “Life is short (but) Art endures.” In essence, it because we are mortal that we want to leave something physical behind, a memento that expresses our life, our being, our experiences, and our perceptions. In fact, all we can really do is stall for time, because nothing, including the earth, the sun, the solar system and maybe even the universe, lasts forever.
In the immortal words of Emily Dickinson (No. 936, c. 1863):
This Dust, and its Feature—
Accredited—Today—
Will in a second Future—
Cease to identify—
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