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Collection Photochrom Prints

Technical Information

Scans of prints in the Photochrom Collection have somewhat different qualities because they were made at different times. The online digital images, even at lower resolutions, play an important preservation role as surrogates that reduce handling of the original pictures. A digital image of each print displays in each bibliographic record. Clicking on this image leads to the high-quality master file and additional derivative files.

Views of Europe and the Middle East

In 2001, Prints & Photographs Division staff members digitized the prints of Russia using an overhead Phase One digital camera in the ITS Scan Center. In 2001-2002, Prints & Photographs Division staff digitized the prints for other countries by using a local flatbed scanner. These images were scanned at 400 pixels per inch producing master TIFF format images with approximately 3,500 pixels on the long side.

Views of North America

In 2008, CSC of Chantilly, Virginia, scanned the photochrom prints that show the United States, Canada, Cuba, and the Bahamas. They used an overhead Sinar 54 digital camera to scan the photochroms at 800 pixles per inch producing master TIFF format images with approximately 7,000 pixels on the long side.  
The specifications for the master and derivative files are:

Uncompressed Archival Images

Spatial Resolution:
Between 3,500 and 7,000 pixels on the long side with the short side scaled in proportion for file names ending in u.tif (17-20 megabytes)
Tonal (pixel depth) resolution:
24 bits per pixel (RGB)
Image enhancement:
File format:
Tagged Image File Format (TIFF) ver. 6.0

Compressed Service Images

Spatial resolution:
640 pixels on the long side with the short side scaled in proportion for file names ending r.jpg (25-190 kilobytes); 1024 pixels on the long side with the short side scaled in proportion for file names ending v.jpg (80-460 kilobytes)
Tonal (pixel depth) resolution:
24 bits per pixel (RGB)
Image enhancement:
Mild sharpening
File format:
Compressed to yield an average compression ratio of 10:1

Thumbnail Images

Spatial Resolution:
150 pixels on the long side with the short side scaled in proportion for file names ending in t.gif (approximately 20 kilobytes)
Tonal (pixel depth) resolution:
24 bits per pixel (RGB)
Image enhancement:
Mild sharpening
File format:
Online copy: GIF - Graphics Interchange Format
Online copy: Compression native to the GIF format

Describing the Information

Most of the Prints and Photographs Division's cataloging is considered "minimal level," because information is often limited to what is provided with the picture rather than what could be learned by fully researching the image. The following comments explain the general cataloging guidelines. They also point out which catalog record information is most useful for citing pictorial materials in research notes or publications. Since the original information accompanying a picture can be inaccurate, the Division is always glad to hear from researchers who have additional or better information. Suggestions can be submitted through the Ask a Librarian e-mail service.

The records for a particular collection might not use each of the following information elements and may not have all of the indexing features described here. For additional information about cataloging pictorial materials, see the Visual Materials: Processing & Cataloging Bibliography.

CALL NUMBER. This string of letters and numbers is used to locate the original material at the Library of Congress. The original work may be requested in order to see details not captured in digital reproduction or to create a new type of copy photograph. A code might display at the end of the call number to identify the custodial division, for example, [P&P] means the item is from the Prints and Photographs Division. Although P&P has a unique system of call number locations (and the patterns vary from filing series to filing series), the call number is still a useful reference citation.

Photochrom Print example: LOT 13419, no. 136 [item] [P&P]

CONTROL #. The control number for each catalog record is a unique identification number. It can be used to do a quick number search when you want to see a specific record without repeating a long keyword or subject search. However, only some online catalogs provide an index by this number.

Photochrom Print example: 2001697529

COLLECTION ("PART OF"). Items are often associated to their source by giving the title of the collection they belong to. This title is useful to include in bibliographic citations. Some items are in more than one collection, because they are associated with both a format-based collection (e.g., Daguerreotype Photograph Filing Series) and a donor-based collection with a single provenance (e.g., Frances Benjamin Johnston Collection). Other items lack a formal collection title heading because they are in collections that have not yet been fully cataloged. Such informal collection names often appear in the NOTES field.

Photochrom Print examples:

  • Forms part of: Views of architecture and other sites primarily in Poland, Russia, and the Ukraine, in the Photochrom print collection.
  • Forms part of: Photochrom Print Collection.

CREATOR. When the name of the photographer, architect, printmaker, or other image creator is known, only one form of the name is used, so that it is possible to retrieve all works by one creator under a single spelling or form of the name. Birth and death dates are included when such information was readily available at the time of cataloging. If the Library of Congress form of the name was established while the creator was still alive, a death date is not usually added when the creator dies. It can be expensive to update such information, and the name is already uniquely identified in the catalog.

The absence of a creator's name indicates that the creator is anonymous, unidentified, or unknown.

After the name, a term often appears to identify the relationship(s) between the name and the work being cataloged. For example, architect, copyright claimant, photographer, or publisher.

Photochrom Print examples:

  • Photoglob Co., publisher  (European and Middle East views)
  • Detroit Photographic Co., publisher  (North American views)

DATE ("CREATED/PUBLISHED"). The date refers to the year(s) when the image being cataloged was created, not the time period depicted in the picture.

The date is transcribed when such information appears with the picture. It can be difficult to assign a specific year to undated prints and photographs. The catalogers look for clues such as: styles of fashion shown in the image, photographer's life dates, or type of physical media. Often, only a span of years or decades is estimated, and such dates are shown in brackets, for example, [between 1900 and 1930].

When the single letter "c" appears before a date, it indicates the year in which an image was copyrighted.

The abbreviation "ca." means "circa" and indicates a date that is approximate within several years.

Photochrom Print examples:

  • [between ca. 1890 and ca. 1900]  (European and Middle East Views)
  • [between 1898 and 1905]  (North American views)

DIGITAL ID. The identification number for the digital file begins with a word or phrase that explains the source used to create the digital image, for example, the "original" work or a "b&w copy film neg." The Library's digital images are often created by scanning one or more of the copy photographs listed in the Reproduction Number field.

The Web address at the end of this field is called a ‘handle' or ‘permanent link' and can be used to uniquely cite or easily return to the image in the catalog.

Photochrom Print examples:

  •  (European and Middle East Views)
  •  (North American views)

FORMATS. The genre and physical characteristics of the original work are listed as plural index terms. Examples include: Broadsides, Engravings, Group portraits, Lithographs--Color, Paintings--Reproductions, Political posters, Portrait photographs, Stereographs, and Woodcuts.
These headings are sometimes subdivided by the nationality, place, or decade in which the work was created. Subdivisions can also indicate if the work is in color or is a reproduction of another medium. The terms come from the Thesaurus for Graphic Materials II: Genre and Physical Characteristic Terms.

Photochrom Print example: Photochrom prints Color 1890-1900.

MEDIUM. The physical properties of the item(s) being cataloged are described by listing a readily recognized broad category, such as photograph, drawing, or print, followed by a more specific designation, such as daguerreotype, charcoal, or aquatint. The medium is determined by examining the item. The description is also a reminder that the physical characteristics of the original item(s) are quite different from a digital reproduction on a computer screen.

The quantity of material is also stated, although most records usually describe only a single item. Some records, however, describe tens or hundreds of items. It is helpful to know the quantity of each work to understand how much material would need to be examined when consulting the original material and also to gauge how general or detailed the information in the catalog record is.

Dimensions are rarely provided in minimal-level cataloging. The storage locations in catalog records provide a general indication of physical size, with "(AA size)" and "(F)" meaning letter-size or smaller, and "E size" being large enough to fill a map case drawer.

Photochrom Print example: 1 photomechanical print : photochrom, color

NOTES, including "RIGHTS INFORMATION." Many types of notes are written to explain reproduction restrictions, sources of devised dates and titles, the name of the collection to which the work belongs, citations to published versions, and other aspects of the work. A subject description is sometimes written if a title is not self-explanatory. With minimal-level cataloging, some types of notes are omitted, for example, acquisition source is rarely provided.

Photochrom Print examples:

  • Title from the Detroit Publishing Co., catalogue J--foreign section, Detroit, Mich. : Detroit Publishing Company, 1905. (European and Middle East Views)
  • Title from item. (North American Views)
  • General information about the Photochrom Print Collection is available at //
  • Detroit Publishing Co. no. "51001"

OTHER TITLE. Additional titles by which the work is known.

RELATED NAMES. When multiple people or corporate bodies contribute to a work, their names can be listed as related, or added, entries. When the nature of the contribution can be specified, a relator term, such as client, copyright claimant, interior designer, or sculptor, is added after the name.

REPOSITORY. The name of the institution and division that have custody of the original work. This information can help you locate or cite the original.

Photochrom Print example: Library of Congress Prints and Photographs Division Washington, D.C. 20540 USA //

REPRODUCTION NUMBER. This alpha-numeric code identifies existing digital files or black-and-white and color photographs from which prints, transparencies, and other reproductions can be ordered. This number is also the most useful (and shortest) reference citation to include with any subsequent publication of an image.

A qualifying phrase identifies the type of reproduction (e.g., color transparency) and points out which reproductions are only details or cropped versions of the original works. This information can help you decide which of the copy photographs you want to reproduce.

The abbreviation "b&w" stands for black-and-white.

Photochrom Print examples:

  • LC-DIG-ppmsc-03921 (digital file from original)  (European and Middle East Views)
  • LC-DIG-ppmsca-17836 (digital file from original item)  (North American views)

SUBJECTS. Catalogers assign index terms that describe what the image shows as well as what the image is about. For example, a political cartoon depicting a basketball game in which the players are dribbling a globe is "of" basketball and "about" international relations. Most of the topical terms come from the Thesaurus for Graphic Materials I: Subject Terms. The proper noun headings come from the Library of Congress Name Authority File and from the Library of Congress Subject Headings. Examples include: Baseball players; Document signings; Dogs; Flags--American; Ford's Theatre (Washington, D.C.); Log cabins; Pan-American Exposition (1901: Buffalo, N.Y.); Presidential inaugurations; Tippecanoe, Battle of, 1811; United States. Declaration of Independence; World War, 1939-1945.

Some collections have only preliminary index headings, and do not use standard vocabulary sources like the Thesaurus for Graphic Materials. For example, the Historic American Buildings Survey uses an uncontrolled indexing vocabulary where different terms, such as "Car dealership" and "Auto dealership," are sometimes used for the same subject, because the material being cataloged used those different terms. The Gottscho-Schleisner Collection headings focus on terms for types of structures, for example, "Automobile dealerships" and use few proper names for subjects such as buildings. (The title includes an informal building or project name taken from the photographer's logbook.)

Subject terms are sometimes subdivided by place and date of depiction.

Place names are sometimes expressed as hierarchical geographic "strings" to allow keyword access to names of countries and states as well as counties and cities. For example, "Canada--British Columbia--Vancouver" or "United States--Maryland- -Baltimore."

Photochrom Print example:
Only the North American views have subject headings. Future plans include adding subject and place names for the European and Middle East views.

TITLE. A title is transcribed from the original picture, or from a photographer's logbook or negative jacket. If the picture carries no caption, a title is devised from another source and displayed in brackets. Devised titles are written by Library staff or might come from a published book illustration or a former owner. Title sources are cited in the notes.

The abbreviations "[sic]" and "[i.e.]" indicate erroneous spellings or information in transcribed titles. The correct information is provided as needed in the title or a note.

Photochrom Print examples:

  • Colorado. Branding calves
  • [Russian church, Warsaw, Russia (i.e. Warsaw, Poland)]

For the European and Middle Eastern views, the English-language title in the Detroit Publishing catalog was used instead of the Russian, French, German and other titles printed on the items. Future plans include adding transcribed titles in multiple languages to represent east picture as it presents itself.