Lincoln Cushing, Docs Populi, 4/2000; most recent update 12/21/2013

Note: This document is now a bit dated, though most of what it covers is still valid. Please contact the author for more current information.

“A Study Guide to Best Practices in Assembling

Digital Catalogs of Political Poster Art”

I. Overview

II. Image-capture methodologies

III. Cataloging software

IV. Metadata content and structure

V. Legal issues

VI. Further areas of work

VII. Additional resources

VIII. Samples of digital catalogs

I. Overview

   Political posters are a vital form of cultural and political expression [1] .  However, their physical size and fragility makes them very difficult to store, they are often produced on archivally unstable paper, and because of the volatile and ephemeral nature of their content are rarely afforded the collecting and curatorial attention afforded other media such as books or records.  These challenges are all powerful arguments for capturing their image, text, and relevant catalog information in more archival and accessible formats.

   As documents, they pose particular problems for digitization and cataloging.  Their physical size makes them relatively awkward to digitize, high resolution scans require enormous memory capacities, and they are an obscure enough document format that there are really no commonly-used standards for meaningful subject classification and metadata coding.  As individuals and institutions begin to take on this formidable task, the need for practical standards and best practices emerges as a primary concern, especially considering the dramatically enhanced information sharing that digital media allows. Functional intercollection research depends on commonly accepted access points, keywords, and formats. 

   This Study Guide has been created to serve as a survey of the broad issues that need to be understood and considered before any organization begins to take on the task of creating a database of images.

   The decision to tackle this task should not be taken lightly.  Even under the best of circumstances it will absorb huge amounts of time, cost more than you expected, and always draw you back for more.  Here are some general questions that one should ask before starting:

1. What sort of materials are likely candidates for this approach? Most two-dimensional items, such as campaign buttons, posters, photos of murals, and t-shirts transfer well to digital format.  Others may not.

2. Is the material unique enough to warrant the work? Cataloging bottle caps found on the street may interest you, but is unlikely to draw much attention from researchers.

3. Has someone else already done it? Can you do it better?  If there is already a complete archive of posters by the Cuban agency OSPAAAL available on-line, perhaps you should work on something else.

In addition, four key elements must be considered before assembling a digital collection: Method and quality of image capture and storage, Cataloging software, Metadata content and structure, and Intellectual property protection.

II. Method and quality of image capture and storage

   Posters are usually larger than 11x17”, the maximum size of most commercially available flatbed scanners.  This leaves two options for digitally capturing the image: shooting it as a transparency and scanning that, or shooting directly with a digital camera.  Either way involves understanding some of the technical issues of image documentation and file formats [2] , [3] .

   The first option involves selecting an appropriate film emulsion, assembling a camera rig with lighting that is color-balanced for that film, and making several shots of each image.  Slides are then scanned, either with a dedicated slide scanner or by using a proprietary commercial system such as Kodak’s Photo-CD system.   A second approach is to digitize images directly. Because posters are so large and need high resolution to adequately capture relevant data, a professional-grade digital camera is usually needed [4] .  In either case, a system for holding the posters flat, positioning the camera perfectly centered and squared on the image, and providing for balanced, even lighting are crucial to successful image capture.  These are not minor tasks.  Many images must be documented, demanding a Taylorist approach to streamlining the task in a manner that is safe for the documents. It is also important to evaluate if you will need to take your show on the road; some collections are too precious or protected to leave their repository, and documentation must be done on-site.

Digitizing method




-Slides shot on the proper emulsion are an archivally-stable medium if properly stored

-Relatively quick capture time, a factor for large-volume work

-Commercial scanning results in inexpensive, multiple-file-size data delivered in handy format    (CD)

-Less control over color balance

-Two-step process takes longer to result in final digital image

-Involves the use of outside vendors

Digital camera

-More control over initial image capture, especially important for posters of varying condition and coloration

-Digital image is available within moments, with all work being accomplished in-house

-Requires on-site large-capacity digital data storage methods

-Best cameras are extremely expensive (~$15,000)


 The final result must be a digital image that meets your needs and, ideally, is useful to others.  The tradeoff is usually large files that are excellent for viewing fine details of the artifact (but take up lots of disk storage and transfer time) versus small files, which have the opposite characteristics. Resources for better understanding technical aspects of digital file formats, file sizes, resolution standards, and storage methodologies are listed at the end of this document.

III. Cataloging software

   Once an image exists in digital form it must be cataloged.  This is necessary for locating the original scan and linking the image to all the relevant catalog information.  Most modern database management programs (such as Microsoft Access or Filemaker Pro) allow this basic process, allowing a displayed thumbnail image to appear along with selected entered data.  Applications geared towards image management (such as Extensis Portfolio) offer advanced features for image display and retrieval. There are also specialized systems that include additional features particularly useful to archives and libraries.  The Getty Museum recently helped the Center for the Study of Political Graphics  (Los Angeles, CA) purchase MultiMIMSY 2000, designed by Willoughby, Inc [5] . They use MIMSY to catalog posters, and to track information about loans, exhibitions, conservation, etc.  The software is designed for museums, rather than archives, and has many museum functions.  It also has several authority files (for people, places, subjects, storage locations, etc.).  The choice of software is largely determined by budget and anticipated needs.

   Cataloging software should ideally offer the following characteristics:

1. Import and export of data from other systems.

2. Scalability (be able to handle as much data as you can throw at it).

3. Export to HTML and ability to access database through the WWW.

4. Cross-platform capability (Mac/PC).

5. Good customer support.

IV. Metadata content and structure

   Describing the image and the cataloged information that accompanies it is known as metadata, and is the cataloging step that most dramatically cries for standardization.  Some file fields will by necessity be purely internal, but most data accompanying a record must be seen as potentially valuable for research.  This topic can be broken down into several elements: Subject Headings and Keywords, Style Protocols, and Format.

1. Subject Headings and Keywords

   Documents need to be clearly described at the beginning if they are to be easily found later.  The conventional approach to this process is to use what is known as a controlled vocabulary, where the terms available are consistent and comprehensive. Not only should these terms be obvious to the cataloger, they should make sense to "outsiders" - researchers, clients, and the public.  Ideally, they should also mesh with terms used in other collections so that the end result is not so idiosyncratic that despite the compelling nature of its content it cannot be joined, filtered, and searched with material from other collections.

   A useful start includes the Library of Congress Subject Headings (LCSH) [6] , the Library of Congress Thesaurus for Graphic Materials [7] , and the Art and Architecture Thesaurus [8] .  However, many of the subjects dealt with in political posters are beyond the scope of standardized subject headings.  This is one area where more collaborative work must be done.

Library of Congress Subject Headings are the standard for thousands of libraries as well as for a multitude of printed indexes. LCSH is the most comprehensive list of subject headings in print in the world. It provides an alphabetical list of all subject headings, cross-references and subdivisions in verified status in the LC subject authority file.

The Thesaurus for Graphic Materials I: Subject Terms (TGM I) provides a substantial body of terms for subject indexing of pictorial materials, particularly the large general collections of historical images which are found in many libraries, historical societies, archives, and museums. It was developed to support the cataloging and retrieval needs of the Library of Congress Prints and Photographs Division, and is offered to other institutions in the hope that it will fill similar needs and will promote standardization in image cataloging. TGM is primarily designed for automated cataloging and indexing systems and is authorized for use in MARC records.

The Art and Architecture Thesaurus is a structured vocabulary that can be used to improve access to information about art, architecture, and material culture. It may be used as a data value standard at the point of documentation or cataloging. In this context, it may be used as a "controlled vocabulary" or "authority." It provides "preferred" terms (or "descriptors") for concepts, as well as other synonyms that could be used by the cataloger or indexer. It also provides structure and classification schemes that can aid in documentation. It may be used as search assistants in database retrieval systems. It is a "knowledge base" that includes semantic networks that show links and paths between concepts, and these relationships can make retrieval more successful. The focus of each vocabulary is art, architecture and material culture.

2. Style Protocols

   Catalog data entry can be seen as a particular style of writing, with many rules regarding precision and consistency. An example - "If the artist's identity is not known, "Artist Unknown" will take the place of the artist's name.  Note that "Artist Unknown" is always written in upper case. [9] " Variation from standards may well result in lost data and imprecise recall.  One authoritative source has been the Anglo American Cataloging Rules (AACR2r), primarily designed for bibliographic material but also applicable to most archival materials. Other guidelines are available that may be more appropriate, but in this case existing standards are quite suitable for the task at hand.

3. Format 

  All document data must be entered into fields.  The ultimate format of the data will ideally be one that is accessible to a wide range of institutions for research and display.

   One common format familiar in the library community is MARC [10] (MAchine-Readable Cataloging record). The MARC 21 formats are standards for the representation and communication of bibliographic and related information in machine-readable form. A MARC record involves three elements: the record structure, the content designation, and the data content of the record.  The structure of MARC records is an implementation of national and international standards, e.g., Information Interchange Format (ANSI Z39.2) and Format for Information Exchange (ISO 2709). Content designation, the codes and conventions established to identify explicitly and characterize further the data elements within a record and to support the manipulation of those data, is defined in the MARC 21 formats. The content of most data elements is defined by standards outside the formats, e.g., Anglo-American Cataloguing Rules or the Library of Congress Subject Headings.

MARC records have their limitations, however, especially regarding non-bibliographic materials.  One of the new standards to emerge is the Encoded Archival Description, or EAD [11] .  The EAD Document Type Definition (DTD) is a standard for encoding archival finding aids using the Standard Generalized Markup Language (SGML). The standard is maintained in the Network Development and MARC Standards Office of the Library of Congress (LC) in partnership with the Society of American Archivists.  MARC records have been in use for many years, and are often the most readily available data structure. For example, the Library of Congress Yanker poster collection provides a MARC-format record of its holdings (see attachment #1) [12] .

   Development of the EAD DTD began with a project initiated by the University of California, Berkeley Library in 1993. The goal of the Berkeley project was to investigate the desirability and feasibility of developing a nonproprietary encoding standard for machine-readable finding aids such as inventories, registers, indexes, and other documents created by archives, libraries, museums, and manuscript repositories to support the use of their holdings. The project directors recognized the growing role of networks in accessing information about holdings, and they were keen to include information beyond that which was provided by traditional machine-readable cataloging (MARC) records. The development of the EAD DTD included the following criteria: 1) ability to present extensive and interrelated descriptive information found in archival finding aids, 2) ability to preserve the hierarchical relationships existing between levels of description, 3) ability to represent descriptive information that is inherited by one hierarchical level from another, 4) ability to move within a hierarchical informational structure, and 5) support for element-specific indexing and retrieval.

   Standard Generalized Markup Language was chosen over other possible solutions because of certain characteristics it possesses. SGML is a set of rules for defining and expressing the logical structure of documents thereby enabling software products to control the searching, retrieval, and structured display of those documents. The rules are applied in the form of markup (tags) that can be embedded in an electronic document to identify and establish relationships among structural parts. Because consistent markup of similarly structured documents is key to successful electronic processing of them, SGML encourages consistency by introducing the concept of a document type definition (or DTD). A DTD prescribes the ordered set of SGML markup tags available for encoding the parts of documents in a similar class. Archival finding aids, which share similar parts and structure, form a class of documents for which a DTD could be and was developed.

   Although it is always preferable to design and enter data in the proper format to begin with, it is also possible to import data fields from one system into another, a process known as retrospective conversion. This is a much more complex task, given the great diversity of existing information in content and format. A recent document from the University of California Encoded Archival Description Project states that “Existing finding aids in typical repositories frequently vary in content in format that reflect both changing intellectual fashions in archival description, and changing technology used in the creation of finding aids. Older finding aids in The Bancroft Library, for example, frequently have a minimum of identifying information, followed by a paragraph or two in which biographical or historical information is intermixed with administrative and scope and content information. This information may or may not be followed by a container list or lists of important correspondents. More recent finding aids generally have more detailed identifying information, and administrative and scope and content information is differentiated [13] .”

   The need for standardization in this area is crucial. A statement from the Planning Conference on UC Implementation of EAD held at UCLA on September 28-29, 1995, put it this way: “The UC Archivists' Council, UC Heads of Special Collections, several systems librarians, and representatives from the UC Division of Library Automation (DLA), Stanford, USC, The Getty Museum, and The Huntington libraries unanimously agreed that a pilot project to prototype a union database of finding aids using EAD would play a critical role in facilitating rapid implementation of the new standard by research libraries throughout California. [14]

V. Intellectual property protection

   Any sharing or display of digital images poses a risk for inappropriate copying and use.  In addition to standard textual warnings about protected material, several methods exist to help identify proprietary material and reduce abuse.

   Without some level of protection, an organization exposes itself to litigation on behalf of the authorized agent, risks trampling the intellectual property rights of the original artist, and jeopardizes the expense of time and money that such a project requires.

   The legal issues surface most prominently at three key points: acquisition, presentation, and contractual use.

1. Acquisition.   The moment images are first gathered is usually the best time to establish authorized use.  The artist and any other relevant parties that may have claim or consideration in the use of the image should sign a release form before the image is documented.  In practice, many organizations may wish to use material for which no release (or an inadequate release) exists; in those cases direct follow up with the artist is the proper course of action.      

2. Presentation. Images must be publicly displayed in a way that both properly credits the originating artist and also clearly describes legal limitations to image re-use by viewers.  In addition, some technical and/or mechanical safeguards should be utilized that will limit unauthorized use.  These safeguards usually include limited-resolution images, watermarking, and advanced encryption protections.

   A common approach is simply to rely on displaying tiny thumbnail (~1x1.5" at 72 dpi) images that are adequate for getting a general impression of the item but are too low a resolution for any reasonable secondary use.

   Watermarked images offer a higher degree of protection for images that are of sufficient resolution to be potentially abused. Various commercial systems are available that allow for some form of encoded identifier to permanently accompany an image and verify its source.  Digimarc [15] is popular one; it is easy to use because its code-embedding software is included in Adobe Photoshop, and it offers a web-spider searching feature that helps the owner learn of new web postings that contain images with the owner's user identification. Other forms of watermark embed a semi-ghosted visual logo across the image, making re-use impractical. It is important to note that these systems do not prevent image theft, they only help prove ownership once it has happened.

   Advanced encryption protection systems such as Secure Image [16] offer elegant methods to display material and still protect it from stealing.  Unlike watermarks, these systems can actually block unauthorized downloading of images by web spiders, they can make screen capture impossible, and they can prevent direct linking of images from another site. They are also relatively expensive, with licenses costing as much as $1500.

3. Contractual use. Finally, any ultimate use of an image can be carefully described by contract. Generally, use contracts include specific language regarding the following subjects, if applicable:

1. Print reproduction conditions including print run, image size, color or black and white, placement, length of use, and geographic distribution, sale/subscription price.

2. Web reproduction conditions, including restrictions on allowing direct links to the image from other sites and duration of use.

3. Image alteration, which can involve some restrictions (especially for fine artwork) that limit the end user's latitude in manipulating the image composition in any way, including flopping, cropping, and changing proportions.

4. Crediting; often there are specific guidelines as to the expected crediting of the artist, including name, date of creation, and title, as well as where that credit should reside and in what format.  It is also not uncommon for supplementary information to be required, such as credit for documentary photographer, location of original artwork, image provider, participating artists, and original client.

5. Copyright protection is often specified, indicating exactly what copyright data must be displayed and where.

6. Political restrictions; some vendors go so far as to try and limit uses incompatible with their mission. For example one GettyOne image of Los Angeles graffiti includes the stated restriction "Cannot be used worldwide for political causes or issues" [17] .

   One approach taken by a major institution (the Library of Congress) is to place responsibility on the patron for any misuse. This is their disclaimer:

“Division Responsibility:

   As a publicly supported institution the Library generally does not own rights to material in its collections. Therefore, it does not charge permission fees for use of such material and cannot give or deny permission to publish or otherwise distribute material in its collections. It is the patron's obligation to determine and satisfy copyright or other use restrictions (such as donor restrictions, privacy rights, publicity rights, licensing and trademarks) when publishing or otherwise distributing materials found in the Division's collections.

   It is the Division's responsibility to inform patrons of any donor restrictions, that is, restrictions on use stipulated by the donor when the collection was transferred to the Library. These agreements between the Library and the donor about use of the collection are separate from the legal rights of copyright, publicity, and privacy discussed in this document. For example, the terms of the gift of the Work of Charles and Ray Eames stipulates that works in the collection may not be published or used commercially without the permission of the Eames Office. This requirement is not a matter of copyright--it is possible that works in the collection may be subject to copyrights held by others--but is the result of the agreement made between the donor and the Library.

   In addition, the Division's staff will attempt to inform patrons about other restrictions when information is readily available [18] ."

VI. Further areas of work

  At present, collections of political poster art in the United States are generally poorly cataloged, under funded, and weakly coordinated. The Yanker collection at the Library of Congress is perhaps the best-known on-line archive of broad material holdings. The Chicano Art collection at U.C. Santa Barbara is well-organized but narrow in scope. Of the two largest known collections the Center for the Study of Political Graphics in Los Angeles is just beginning to document and catalog their holdings, and the AOUON Archive gathered by Michael Rossman in Berkeley is still largely inaccessible.  Numerous smaller archives and collections await identification and cataloging.

   What is needed is a clearinghouse for helping to coordinate efforts by various interested parties to facilitate enormous task of documenting and cataloging these materials in a manner that will allow reasonable public access and research across collections.  Such coordination will result in more efficient practices, greater use of standards, and appropriate collaboration to avoid unnecessary duplication of efforts.  It is my hope that Docs Populi can help serve this function.

VII. Additional resources

Project overview

Planning Digital Projects for Historical Collections, New York Public Library;

Image capture and storage

Digitizing Historical Pictorial Collections for the Internet, by Stephen E. Ostrow, February 1998;

Digital Imaging for Photographic Collections, by Franziska S. Frey and James M. Reilly, published by the Image Permanence Institute;

Cataloging software

Extensis Portfolio;

Canto Cumulus;

Willoughby, museum systems;

Metadata content and structure

Subject Heading Terms Used for Photographs in the Walter P. Reuther Labor Collections, by Amy L. James;

Style Protocol and Format for Silkscreen Catalogs, developed for the collections at U.C. Santa Barbara;

Cataloging Issues for Image Databases of Historical Artifacts;

Examples of Digital Archives and Galleries

American University of Beirut – Jaffet Library; Political posters collected between the 1960s and the 1980s;

International Institute of Social History; posters of Cuba, China, the Soviet Union, European labor and women’s history;

Powers of persuasion – Poster art from World War II;

Chicano Visual Arts Digital Image Collection, U.C.Berkeley;

The Sixties project – Special Exhibitions;

Collection of 700 posters from Russia, Czech republic, Poland and Cuba; a commercial site, but useful resource;

Herbert Hoover Memorial Exhibit Pavilion (of the Hoover Institution, Stanford, California);

The Yanker Collection, Library of Congress (this is the currently the largest on-line image-linked catalog of poster art in the U.S.);

Graphic Witness – Visual Arts and Social Commentary;

Art for a Change (student site from UC San Diego) includes Paris 1968 images, contemporary artists, and more;

Documents from the Women's Liberation Movement; An On-line Archival Collection Special Collections Library, Duke University;

Transnational Poster Art: Former East Germany (GDR) and Latin America 1970-1989 (project affiliated with Stanford University Libraries);

Picturing Power- posters from the Chinese cultural revolution (Exhibit 8/99-10/99, East Asian Studies Center, Indiana University, Bloomington);

[1] “Political poster” is a term that broadly includes 2-dimensional paper-based printed documents with an explicit ideological message.  These include multiple subcategories that allow for the full spectrum of political values as well as national and international origin, and include posters for electoral campaigns, propaganda efforts, opposition to dominant culture and politics, and solidarity with movements for peace and social justice. (Author's definition)

[2] Digitizing Historical Pictorial Collections for the Internet, by Stephen E. Ostrow, February 1998;

[3] Digital Imaging for Photographic Collections, by Franziska S. Frey and James M. Reilly, published by the Image Permanence Institute;






[9] Style Protocol and Format for Silkscreen Catalogs, CEMA, U.C. Santa Barbara



[12], pick a subject, (Opposition -- Political science -- Chile), pick a title, (12.Chile: active resistance demands active solidarity), and select “View the MARC Record for this item” at bottom of screen.





[17],  (enter “eb1307-001” Search Options); “Graffiti artist at graffiti yard, Los Angeles, California, USA”, Stone photo agency, Robert Yager photographer