Photographic Standard
A 75-year-permanence standard is intended to ensure the longevity of NR-NHL documentation and applies to all forms of photodocumentation, including those types of photographs currently available and any introduced in the future. Black-and-white images printed on silver-emulsion fiber-based papers and black-and-white images printed on silver-emulsion resin-coated (RC) papers have been acceptable for some time. As of this writing, black-and-white prints produced from digital images that have been demonstrated to meet or exceed a 75-year permanence standard also are acceptable. The Federal government does not endorse any particular commercial product or process. A non-comprehensive list of photographic ink and paper combinations that have been demonstrated to meet the 75-year permanence standard may be found under the Digital Photographs section as guidance for implementing this policy expansion. No photos processed with chromogenic processing (C-41) or printed on chromogenic papers currently meet the established standard and are, therefore, not acceptable; however, this may change with future innovations.

Prints produced from digital photographs submitted as official documentation must be accompanied by corresponding electronic image files. Electronic image files must be saved as uncompressed .TIF (Tagged Image File format) files on CD-R media, in keeping with guidance on digital photographic records issued by the U.S. National Archives and Records Administration. The size of each image must be 1600x1200 pixels at 300 ppi (pixels per inch) or larger. It is recommended that digital images be saved in 8-bit (or larger) color format, which provides maximum detail even when printed in black-and-white. The file name for each electronic image saved on the CD-R must correspond with the photo log included in the nomination and the information labeled on the back of each photograph, and it should also reference the state and county in which the property is located. For example, the image files for the James Smith House in Jefferson County, Alabama, would be saved as “AL_JeffersonCounty_Smith1.tif,” “AL_JeffersonCounty_Smith2.tif,” and so forth.

In the case of a large historic district, it is optional to add the inventory number of the property to the end of the digital image file name. That number should correspond to the historic district mapping and inventory documentation. For example, for a photo depicting building #20 in the Montpelier Historic District, we would suggest: "VT_WashingtonCounty_MontpelierHD89_Property20.tif" (89 indicates that it is the 89th photo of the historic district, and 20 indicates that it is building #20 as identified in the district inventory and map).

CD-Rs submitted with a nomination must be labeled with:

• the name of the property.
• the associated multiple property documentation form (if applicable).
• the county and state where the property is located.

Basic Requirements
Labeling Photographs
Use of National Register Photographs
Guidelines for Photographic Coverage
Guidance on Implementing the Standard
Digital Photographs
Acceptable Ink and Paper Combinations For Digital Images
Photographic Technology
For Further Information

Basic Requirements
Photographs must be:

• unmounted (do not affix photographs to archival paper or any other material using staples, paper clips, glue, or other means).
• at least 3½ x 5 inches.
• properly processed and thoroughly washed.
• labeled in pencil or archival photo-labeling pen.

Labeling Photographs
Two methods of labeling photographs are acceptable. Labeling may be done by printing in pencil (soft lead works best) or with an archival photo-labeling pen on the back of each photograph. The following information must be included:

1. Name of the property or, for districts, the name of the building or street address followed by the name of the district.
2. County and state where the property is located.
3. Name of the photographer.
4. Date of photograph.
5. Location of original negative (if film is used).
6. Description of view indicating direction of camera.
7. Photograph number. For districts, use this number to identify the vantage point on the accompanying sketch map.

An alternative method of labeling is to use a continuation sheet(s). The photographs should be labeled in the manner described above with the name of the property, county and state, and photo number (items 1, 2, and 7). Then, on a separate continuation sheet, list the remaining information (items 3-6). Information common to all photographs, such as the photographer’s name or the location of negatives, may be listed once in a statement on the continuation sheet.

Use of National Register Photographs
By allowing a photograph to be submitted as official documentation, photographers grant permission to the National Park Service to use the photograph for print and electronic publication and other purposes, including but not limited to duplication, display, distribution, study, publicity, and audiovisual presentations.

Guidelines for Photographic Coverage
Photographs submitted to the National Register of Historic Places and the National Historic Landmarks Survey as official documentation should be clear, well-composed, and provide an accurate visual representation of the property and its significant features. They must illustrate the qualities discussed in the description and statement of significance. Photographs should show historically significant features and also any alterations that have affected the property’s historic integrity.

The necessary number of photographic views depends on the size and complexity of the property. Submit as many photographs as needed to depict the current condition and significant features of the property. A few photographs may be sufficient to document a single building or object. Larger, more complex properties and historic districts will require a number of photos. Prints of historic photographs may supplement photodocumentation and be particularly useful in illustrating changes that have occurred over time.

Buildings, structures, and objects:

• Submit photographs showing the principal facades and the setting in which the property is located.
• Additions, alterations, intrusions, and dependencies should appear in the photographs.
• Include views of interiors, outbuildings, landscaping, or unusual features if they contribute to the significance of the property.

Historic and archeological sites:

• Submit photographs showing the condition of the site and any above-ground or surface features and disturbances.
• If relevant to the evaluation of significance, include drawings or photographs illustrating artifacts that have been removed from the site.
• At least one photograph must show the physical environment and topography of the site.

Architectural and Historic Districts:

• Submit photographs showing major building types and styles, pivotal buildings and structures, and representative noncontributing resources.
• Streetscapes and landscapes are recommended. Aerial views may also be useful. Views of significant topographic features and spatial elements should also be submitted.
• Views of individual buildings are not necessary if streetscape views clearly illustrate the significant historical and architectural qualities of the district.
• Key all photographs to the sketch map for the district.

Archeological Districts:

• Submit photographs of the principal sites and site types within the district following the guidelines for archaeological sites (see above).

Guidance on Implementing the Standard
Black-and-white prints have been required since the inception of both the National Register and National Historic Landmarks programs because of their superior permanence. The longevity of a photograph depends on the materials and processing methods used and the conditions under which it is stored. The NR-NHL collections are maintained at the National Park Service offices in Washington, D.C., and are stored under climate-controlled conditions. Each nomination is placed in an acid-free file folder, with photographs stored in a separate acid-free sleeve. The conditions under which nominations are stored are designed for archival longevity. To make certain that nominations last as long as possible, it is essential that nomination preparers and nominating authorities submit photographs that meet the NR-NHL standards. Ensuring the longevity of official documentation, including photographs, is essential for the administration of federal historic preservation programs. In addition to the regulatory protections and grants and tax incentives available under federal law to properties listed in the National Register or as National Historic Landmarks, the nomination files for these programs constitute an irreplaceable archive of American history.

When the National Register and National Historic Landmarks Survey were established, black-and-white prints were generally made using silver-emulsion fiber-based paper, which has outstanding archival stability. If stored under proper conditions, black-and-white prints on fiber-based paper will easily last 150 years or more. In the late 1970s, resin-coated (RC) papers became popular because of their lower cost and ease of processing. Use of fiber-based papers consequently became limited to specialized applications. In response to these changes, the National Register and National Historic Landmarks Survey began accepting photographs printed on RC paper in the early 1980s. The limitations of this policy became clear in recent years with the advent of digital photography, the introduction of black-and-white films that can be developed and printed using color (C-41) processing, and the declining use of conventional black-and-white photography. The use of the 75-year permanence standard for all forms of photo documentation, no matter what methods are used to produce the photographs in question, ensures that the photo policy will continue to be applicable as manufacturers introduce new products and discontinue others. It provides a basis for evaluating all currently available photographic materials and those introduced in the future.

Nominating authorities and nomination preparers are advised that manufacturers’ claims may sometimes overstate the expected longevity of products. In some cases, nominating authorities may be required to provide verifiable information referencing tests conducted by an independent laboratory to demonstrate that the prints in question meet the 75-year permanence standard. This does not mean that nominating authorities will be expected to contract with independent laboratories to test photographic materials or required to submit test data with each nomination. It may, however, be necessary to research the expected permanency of photographs when evaluating new photographic materials or processing methods. Nominating authorities are advised to consult the sources included in the For Further Information section to identify photographic materials and processing methods that meet the 75-year permanence standard. Other valuable sources of guidance include curators and archivists who specialize in photographs at state archives, libraries, and colleges and universities. In addition, manufacturers sometimes make available results of independent testing.

Nominating authorities and nomination preparers should also be aware that the proliferation of so-called “archival” products has made it difficult to identify products that meet the NR-NHL documentation standards. No firm, universally acceptable definition of archival exists, and many manufacturers now use the term for marketing purposes. In some instances, products labeled archival will last considerably longer than non-archival products but may not meet the NR-NHL standards. Independent testing has shown that some popular photographic papers marketed as archival, for example, will begin deteriorating in far less than 75 years and therefore cannot be accepted as official documentation. Therefore, archival products should not be accepted at face value but only if they meet the NR-NHL documentation standards.

Digital Photographs
Several options are available for nominating authorities who wish to submit photographic prints produced from digital images. Consulting a photo lab in your area that offers professional services is a good starting point. A number of commercial processing methods produce high-quality prints from digital images that meet the NR-NHL standards. If digital services that produce acceptable images at reasonable cost are locally available, this may prove satisfactory for many nominating authorities.

Another option is to produce prints in-house with an inkjet or dye-sublimation photo printer that can use special archival inks and photo papers. While most photo printers made for the consumer market are designed to produce color prints that last only a few years before fading, a number of manufacturers now offer models which, with the correct inks and papers, can produce prints with an expected lifespan comparable to or better than traditional black-and-white prints on RC paper. These printers can be obtained at reasonable cost. Producing photographic prints in-house may result in long-term cost savings and also offers the important advantage of providing control over the imaging process.

Acceptable Ink and Paper Combinations For Digital Images
The non-comprehensive list below includes products that meet the NR-NHL permanence standard. Specific printers are not identified, as the longevity of a print is dependent on the ink and paper combinations used to produce it, rather than on the printer.

Photographic Technology
The following information about basic types of photographic materials and processing methods is intended to help nominating authorities and nomination preparers obtain photographs that meet the NR-NHL standards. It addresses questions about currently available products and commonly used terms that have compounded the difficulty of obtaining acceptable photographs. While not comprehensive, this guidance provides information for making informed choices among the vast range of products available in the photographic marketplace.

The new technologies and photographic materials introduced in recent years have produced the most dramatic changes in photography since the advent of color films and printing papers in the 1960s. One consequence of these changes is the reduced availability of conventional black-and-white films, papers, and processing. In many cases, photographic labs capable of producing high-quality black-and-white photographs can be found only in major metropolitan areas. Declining demand for traditional black-and-white photography has resulted in significantly higher costs, which places an added burden on nominating authorities and nomination preparers. At the same time, improvements in digital technology have resulted in the availability of black-and-white prints that can be obtained at reasonable cost and meet the NR-NHL documentation standards.

Much of the recent confusion faced by nominating authorities and nomination preparers stems from the introduction of chromogenic black-and-white films, which share more similarities with color films than traditional black-and-white films. Chromogenic black-and-white films, produced by manufacturers such as Kodak and Illford, are processed and printed using C-41 processing, the method most commonly used for color photographs. Unlike traditional black-and-white films, the silver-halide crystals in the emulsion layer of a chromogenic film are replaced with dyes during the developing process, in the same way that occurs in processing color film. Chromogenic black-and-white films, which can be developed at one-hour photo labs and similar facilities, make it possible for photographers to obtain black-and-white prints quickly and at low cost. The longevity of these prints, however, tends to be poor. Because they are produced with color developing and processing methods and are printed on color paper, they are essentially color photographs. As a result, they do not meet the NR-NHL standards.

Like conventional photographs, the longevity of prints made with digital imaging technology depends largely on the materials and ink used. Improvements in technology and growing demand for digital prints have led manufacturers to introduce new photo papers, inks, and printing systems, and it is now possible to obtain photographs made from digital images that equal or surpass the longevity of conventional black-and-white photographs on RC paper. Prints made from digital images are available from photo labs that offer digital services or can be produced using printers and photo materials widely available to consumers. Available types of digital printing papers include versions similar to traditional RC and fiber-based black-and-white papers. As with conventional photographic materials, the National Register and National Historic Landmarks Survey recommend that nominating authorities conduct careful research and check manufacturers’ claims against independent laboratory testing before selecting digital photo products.

For Further Information
Because of continual changes in photographic technology, determining the longevity of photographic materials will continue to be challenging. The National Register and National Historic Landmarks Survey cannot undertake detailed study of new products as they become available. SHPOs, FPOs, and TPOs are encouraged to bring new imaging technologies that appear to meet the NR-NHL documentation standards to the attention of the NR-NHL staff. Nominating authorities and nomination preparers are encouraged to consult reputable sources of information in selecting photographs to be submitted as official documentation. Curators and archivists who specialize in photographs at state archives, libraries, colleges and universities can often offer valuable guidance. The most current information can usually be found on-line. In expanding this photo policy, the following websites were helpful:

American Institute for Conservation of Historic and Artistic Works:
Professional membership organization for conservators, including specialists with photographic materials. A public guide to caring for photographs is available online. See also the “Find a Conservator” link for access to an online database of AIC members, which is a quick and easy way to find a trained photo conservator in your area.

Wilhelm Imaging Research: www.wilhelm-research.com
Henry Wilhelm is widely recognized as a leading authority on the stability and preservation of traditional and digital photographs. He conducts research on photo materials and provides consulting services to museums, archives, and commercial clients. The Wilhelm Imaging Research website includes data from permanence studies and articles by Wilhelm. This data is particularly useful when trying to determine if a particular type of photographic print will meet the National Register standards.

Manufacturers’ websites provide useful information about commercially-available products.
Eastman Kodak Company: www.kodak.com
Fujifilm USA: www.fujifilm.com
The Epson Company: www.epson.com/northarmerica.html

RLG DigiNews:
Bimonthly web-based newsletter focusing on digital imaging and practices in image conservation and digital archiving. Produced by the Department of Research of Cornell University Libraries for RLG, an international nonprofit organization of libraries, archives, and museums.

California Digital Library Digital Format Standards (2001):
Standards published by the California Digital Library at the University of California. Provides recommendations for image quality, file formats, and storage media.

Columbia University Libraries, Technical Recommendations for Digital Imaging Projects (1997):
Digital imaging recommendations prepared by the Image Quality Working Group of ArchivesCom, a joint effort of Columbia University Libraries and Academic Information Systems at Columbia University.

National Archives and Records Administration Guidance on Digital Photographic Records:
Provides guidance on digital photographic records, including images captured by digital cameras.

National Archives and Records Administration Guidance on Scanned Images of Textual Records:
Although concerned only with scanned images of textual records, this document includes guidance on digital file formats.