1. Search Tips
  2. Not finding enough?
  3. Finding too much?
  4. Searching by time period and place
  5. Searching
    by number
    (digital id.,
    reproduction, call numbers)
  6. Don’t ignore “Group Record” links
    and links within records
  1. Downloading and Linking tips
  2. Frequently asked questions

1. Search Tips

  • You can use either capital or lowercase letters. Case does not affect the results of your search.
  • You can enter words in any order.
  • Some punctuation and special characters (for example, letters with diacritcs) throw off the search. If you get zero results, try re-entering the search without those characters.

2. Not Finding Enough?

  • Use the “Search all” blank on the home page to search everything in the catalog at once rather
    than searching a single collection
  • Use fewer words (many “inventory level” records
    include only information from a caption or
    caption card, so, for instance, an individual’s
    first name may not be included or fully spelled
  • Check spelling and spacing of search word(s): Are there alternate spellings? Could two words have been combined into one (or vice versa) in image captions? Have you used abbreviations that can be spelled out?
  • Try using wildcards to enable the search to include variations on a word (E.g., child* retrieves child, children, childlike)
  • Try selecting from lists of terms in the “Browse By” offerings at the left of the search screen.
  • Try “View all” records or images to see if this gives clues about the kinds of images that are in a collection or the kinds of words that are in the descriptions.
  • Look through the list of collections with descriptions.
    Is the image you are looking for something
    we are likely to have? (E.g., art reproductions, photos of very recent news events, and illustrations of ancient
    peoples are not strengths of our collections.) For information about what the catalog includes, see “About the Prints & Photographs Online Catalog”

3. Finding Too Much?

  • In the Advanced search, select to “match all words” or to “match exact phrase.” Select “No variants” to eliminate words with alternate endings.
  • Look through the list of collections with descriptions.
    Is the image you are looking for something
    we are likely to have? (E.g., art reproductions,
    recent news photos, and illustrations of ancient
    peoples are not strengths of our collections.)
  • Try selecting from lists of terms in the “Browse By” offerings at the left of the search screen. Note: Selecting a heading retrieves only records with that exact heading, not records that contain words from the heading. Example: If you select the subject heading “Wales” from a browse list, the system will retrieve records that contain the subject heading “Wales” but not those that have the subject heading “Wales–Rhyl.”
  • Try searching the Thesaurus for Graphic Materials to see what standardized terms we use to index images you might be interested in.

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4. Searching by time period and place

Time period

At present, there is no simple, precise way to search
for a date or time period.

  • You can search
    for a year or a span of years. But the appearance
    of the date or the particular string of numbers
    anywhere in the record will cause the record to be retrieved, so you may get records for items whose
    artist was born in that year, or records that
    include a four digit address.
    Note: Catalog
    records often use estimated dates or multiple
    dates that are expressed as a range of years.
    If your year falls within that range, it will
    not be retrieved. Try neighboring years that end in 5 or 0, e.g., 1750, 1755
  • Subject headings often include a chronological
    component that is expressed in decades. For
    instance, if the item was produced or depicts
    something in 1844, the subject subdivision
    will be 1840-1850. So you might try
    searching for decades that would be relevant.


It is best to try both specific place names
and the names of the larger geographic juridictions
when searching geographically.

  • Some catalog records include a hierarchy
    of the places represented by an image or set
    of images, going from the larger geographic
    unit to the smaller. Example: Canada–British
    Columbia–Columbia Mountains
  • In other cases, only the specific place is mentioned,
    sometimes with an abbreviation for the larger
    geographic jurisdiction. Example: Los
    Angeles (Calif.)

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5. Searching by number (digital id., reproduction,
call numbers)

What are these different numbers?

  • Call numbers: A string
    of letters and numbers used to locate the
    original material filed at the Library of
    Congress. Example: POS – WPA – ILL .B46, no. 7 (B size)
  • Reproduction numbers: An
    alpha-numeric code that identifies existing
    black-and-white and color negatives, slides,
    or transparencies or high quality digital
    scans from which prints, transparencies, and
    other reproductions can be ordered. Example: LC-USZC4-1587
  • Digital ID numbers: An
    alpha-numeric code that is the unique identifier
    for a digital image displaying in the catalog. Example: cph 3b53089

All of these types of numbers are formulated
in different ways in different collections.
For instance, in some collections, negative
numbers include “leading zeros” that must be included in order for the record to be found (e.g., LC-USF34-007820).

Searching for a Specific Number

The most precise way to search for a number is to search it as a phrase. You can either:

    • search the number with quotes around it: “LC-USF34-007820”


  • select “Advanced” search and use the pull-down menu to “Match exact phrase”

To add further precision to the search, you can designate your search a “Number” search:

  • select “Advanced” search and use the pull-down menu to “Search the number fields “

Searching by Digital ID

You may start with different information, depending
upon whether you got the number by looking at
a description or display page or by copying down the number
when displaying the image. Some general rules
of thumb for searching digital
id. numbers are:

If you see a string that includes the format or a URL beginning with “hdl,” type the final letters and numbers


You see:
Digital ID: (b&w film copy neg.) cph 3c07395
You type:

If you’re starting with a digital
file name that ends with
r.jpg, v.jpg, or u.tif

You type: The letter/number string
after the final slash, dropping
the “r.jpg,” “v.jpg,” or “u.tif” part.

Example: You have a file that is called: 3c07395r.jpg. To retrieve it in the catalog, type: 3c07395

Occasionally, a digital file is part of a set
of images that do not have individual catalog
records, and you need to retrieve the record
for the whole set and then page through the
images to locate the item.

If you see: A digital file name that
ends with two sets of numbers, seemingly not
numerically related (or you simply
try searching the final set
of numbers, dropping the letters as instructed
above, and get no result)
You type: The second to the last set of numbers
(or, more precisely, the second to the last set
of numbers, and the letters appearing after


You see:
You type: 00991 (or pplot

The Historic American Buildings Survey/Historic American Engineering Record/Historic American Landscapes Survey images are presented in sets (surveys). Rather than searching for an individual image in the survey, you must retrieve the description for the particular survey and then display the images. In the path name for the image, you would search by the letter-number combination that appears before the format designation.

You see:
You type: nm0099

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6. Don’t ignore “Group Record” links and links
within records!

Some group records contain links to images
and/or links to further information within them.


  • HABS/HAER/HALS records contain links
    to different types of documentation:
    HABS/HAER/HALS icons for multiple types of architectural documentation
  • Records for groups of images (LOTs
    or ADE UNITs); all or some of the items
    may have been cataloged and digitized
    as people requested reproductions

    Select the “Check for online items from this group” link to the left of the description.

  • Some groups of images have been
    digitized but not individually cataloged
    . Select the icon that indicates that you can click for more images.
  • FSA/OWI records have links that
    allow you to see related images that do
    not have titles and are not indexed by
    photographer, because they were not captioned
    or printed at the time the images were
    . Selecting the “Browse neighboring items by call number” to the left of the description to view these untitled images.
  • Some item records that have very brief
    information may be fleshed out by selecting
    the “Check for online group record (may link to related items)” link, in order to find out about
    the group the item comes from. Not all items
    have a corresponding group record.

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7. Downloading and
Linking Tips

Downloading Image Files

The Prints & Photographs Online Catalog
includes images in the following formats:

  • gif – generally small “thumbnails” used
    for previewing images; a gif image
    displays at the top of its associated catalog
    record and, in some cases, it is the only
    image that will display to those searching
    outside the Library of Congress because of
    rights considerations (extension on the file
    name is .gif). The resolution is
    generally about 150×150 pixels.
  • jpeg – generally a larger
    image that displays in a separate screen from
    the catalog record; sometimes two types of
    jpeg files are available–one for reference
    viewing and one at a higher resolution (extension
    on the file name is .jpg).
  • tiff– generally the highest
    resolution file available in PPOC, viewed
    or downloaded via a link on the screen where
    the reference jpeg displays (extension on
    the file name is .tif).

Information on software for viewing tiffs can
be found in a document on the American Memory
web site: How to View Prints
and Photographs

In cases where the rights to an image have
not been evaluated or are known to be restricted,
.jpg and .tif images will not display to those
searching outside of the Library of Congress.

We occasionally get reports that individuals
have difficulty saving .tif files, even when
the link is visible to them. One possible explanation
for this is that the file is large (many .tif
files exceed 10 megatbytes, and some are as
large as 200 megabytes or more). Particularly when using
a dial-up connection, it can take considerable
time to open or save such a file. It is best,
in these instances, to try to save the file
without first opening it. Browsers and helper
applications vary in how they present downloading
options and steps. The following are the general
steps for saving files.

To save images:

  1. Place your mouse over the image of the desired
    jpeg or tiff link.
  2. Click the right mouse button (PC) or hold the control key while clicking to get the dialogue box (Macintosh OSX. For earlier versions: depress and hold the single button of the mouse).
  3. A menu will appear.
    • Select Save image as or Save
      Picture as
      if you moused over
      an image.
    • Select Save target as or Save
      link as
      if you moused over a
  4. A box will appear in which you indicate
    your desired name of the image file and where
    you wish it to be saved. Note: Web images
    often have non-intuitive file names (ex. 1a34653u.tif)-you
    may want to rename the image to something
    you will understand later (e.g., railroad.tif).

Image Resolution

The quality of the digital images varies greatly,
depending upon when and from what source the
digitizing was done. In general, digital files
that are considered of high enough resolution
for the Library’s
Photoduplication Service to make a quality reproduction
from it include an “LC-DIG…” type of number
in the reproduction number field.

Gauging the “dots per inch” (dpi)
of an image file

Images found in the Prints & Photographs
Online Catalog vary considerably in resolution.
The size of the original or copy that was scanned
also varies, making it difficult to state the “dpi” of
any given file.

When using an image you have downloaded from
the catalog, the “dpi” is partially
determined by the size with which you intend
to reproduce the image. Most image software
enables you to set the desired size and then
view the resulting dpi or, conversely, to set
the desired dpi and see what size image can
be reproduced at that level.

Here’s a rough and ready way to estimate what
dpi you will get based on the size of the image
file: divide the pixel dimensions for the digital
image by the dots per inch you wish to achieve–this
will tell you what size the image will need
to be.


  • Find out the dimensions of the digital
    image. One easy way to do this is to right-click
    on the image, and look at the image properties.
    When viewing TIFF images, you may need to
    select a choice such as “About…” in
    your viewer.
  • The image properties tells you the scan
    is 720 x 1024 pixels.
  • For a 300 dpi result, divide each pixel
    dimension by 300, and you’ll know roughly
    how large the scan can be printed and be called
    300 dpi.720 / 300 = 2

    1024 / 300 = 3
    As long as the image printed from this particular
    file is not much beyond 2 x 3 inches, it
    will be in the 300 dpi ballpark.

Linking to Particular Records

Use the “Share/Save” links at the top. The “Share/Save” feature enables you to link to any individual record, set of search results, or individual page within PPOC.

Other options: copy the URL in your browser’s address window and use that as a link.

– if a “handle” (a URL beginning “ . . .”) is displaying with an image, you can use that to link to the image display; it is the permanent address for the digital item.

– to link to the description, use the URL appearing after “Bookmark This Record:” at the bottom of the description

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8. Frequently Asked Questions

Why aren’t images displaying?

  • Not all pictures described in the Prints & Photographs Online Catalog are digitized. A “Not digitized” image usually indicates this for descriptions of single items.
  • In cases where a rights holder has indicated they do not wish larger images to display outside the Library of Congress or the rights to the image have not been evaluated, only a thumbnail (.gif) image will be available to searchers outside the Library of Congress.
  • The list of collections with descriptions and each collection page includes information regarding whether the collection has been digitized and whether larger images will display outside the Library of Congress.
  • If the collection description indicates that images should be displaying at your location, you may want to check to see whether graphics have been turned off on your browser. If a “broken” graphic appears, there may be a problem with the link to the image or a temporary server problem.

Why don’t I find images I know the
Prints & Photographs
Division holds?

Not all of the holdings of the
Prints & Photographs
Division are represented by online catalog records.
Some popular images cataloged years ago are
so far only accessible through manual files in
Prints & Photographs Reading Room. Some
images are cataloged in groups, so your image
may not have an individual entry. If you have
correctly entered various search terms, searching
broadly across all collections/categories using a general keyword (not a specific field) search and still have
not found the material you are seeking, you
may want to check with us through the Ask
a Librarian
service. For further information about
what is in the catalog, see About
the Prints & Photographs Online Catalog

How do I obtain copies
of material found through the catalog?

is possible to download many images from the
online catalog. See Downloading
and Linking tips

Quality copies of most images
listed in PPOC can be purchased from
Library of Congress
Selecting the “Obtaining Copies” tab when you are displaying an individual record will provide
you with the information you will need to place
an order.

Why am I having problems viewing/downloading this tiff image?

We occasionally get reports that individuals
have difficulty viewing or saving tiff files, even when
the link is visible to them. There are a few possible explanations for this:

  1. The file is large. It may be that it is simply very slow to load; particularly when using
    a slower connection, it can take considerable
    time to open or save TIFF files, some of which exceed 100 mb.
  2. It is a 16 bit file. If it is labeled “Highest Resolution TIFF Image,” it is a 16 bit image; many older viewing softwares are not configured to handle 16 bit images. It is best,
    in these instances, to try to save the file
    without first opening it (see Downloading and
    Linking tips
  3. Some TIFF images display more successfully in one browser software than another (e.g., an image may display in Firefox that does not display in Internet Explorer). The symptom of this problem is often that, once the TIFF image loads, you just get a series of strange text charaters. Try another browser. (You are also welcome to report the problem via our Ask a Librarian service, and we’ll request to have the image adjusted for use in all browsers.) [view Ask a Librarian form – please include the REPRODUCTION NUMBER or DIGITAL ID]
  4. QuickTime may be trying to display the tiff image. In general, JPEG files are
    viewed directly in Web browser software while TIFF files are viewed using a plug-in
    or separate software outside the Web browser. For some, this plugin is set to
    QuickTime, which can be a problem, because QuickTime cannot display every type of
    TIFF file in use on the Internet, including some presented on the Library of
    Congress Web site.

    Your options are to save the files directly without attempting to display them or
    to change some settings on your computer or in your browser’s settings.

    Save without displaying

    The easiest work-around is to save the TIFF files without attempting to display

    a. Right-mouse-click (or control-click, particularly with a one-button mouse) on
    the text link for the TIFF file. This is not the usual clicking button — it’s
    the other one.

    b. On the menu, select Select quot;save target asquot; (with Internet Explorer) or “save
    link as” (with Firefox).

    c. In the box that appears:
    – Select where you want the image to be saved.
    – Give the file a name meaningful to you (with the quot;.tifquot; extension for the
    TIF/TIFF file or if you have selected the JPEG format, with the .jpg extension).
    – Click the save button.

    Browser setting adjustments

    With Firefox, settings for viewing TIFF files are inside Firefox’s preferences.
    One thing you can do is to verify that Firefox knows to view TIFF in something
    other than QuickTime. Select quot;tools,quot; then quot;optionsquot; and then quot;applications.quot;
    Scroll down the list and look for any reference to TIFF, TIF, or quot;image/tiff,quot;
    or quot;image/x-tiff,quot; and so on. Make sure than none of these points to QuickTime.
    To change an entry, click on it and then you’ll notice a pull-down appears to
    the right of the file format name. Choose another application from what appears
    in the pull down, or select “use other” and scroll down for another appropriate
    software title. If you still don’t like the options, select “browse” and find
    one on your computer.

    With Internet Explorer and Safari, these settings are tied to the operating
    systems: Windows and OSX. Usually on MacIntosh computers TIFF is set to either
    Preview, which usually works pretty well, or the QuickTime picture viewer.
    In Windows, the default setting is often the Windows Picture Viewer, which
    works much of the time, but might fail for very large image files.

    Sometimes, it looks like the defaults are set to something other than QuickTime,
    but it doesn’t seem to matter; when this is the case, you may wish to change
    some settings in QuickTime.

    Changing QuickTime settings

    The method varies a little from version to version. Here is how it works on
    a Windows computer, which has QuickTime, version 7.

    a. Open the QuickTime Player (not the picture viewer) from the Start Menu.
    b. Find quot;preferences.quot; On the version on my computer, it is in the “edit” menu.
    c. Select quot;QuickTime Preferences.quot;
    d. Click the quot;Browserquot; Tab.
    e. Click the quot;Mime Settingsquot; button.
    f. Click the quot;+quot; next to quot;images.quot;
    g. Un-check quot;TIFF imagesquot; (and any other formats you no longer want Quicktime to open
    while you are browsing the Web. I recommend you leave at least these two formats checked:
    MacPaint, QuickTime image.)

    For information on finding TIFF viewers other than QuickTime, see the American Memory
    guidance on “How to
    View Prints and Photographs.”

size is the original image?

If the size of the original image has been
recorded in the online record, it will be found
in the MEDIUM field.

Many online catalog records do not include
the measurements of the original item, because
of the resources it takes to record this information
and the uncertainties that can occur in measuring
images of various types.

In some cases, a general size range can be
gleaned from a filing designation given in the
CALL NUMBER field. Letter designations that
appear at the end of many Prints & Photographs
Division call numbers for individual prints,
photographs, and drawings (posters are an exception)
indicate the size of the container in which
the item is housed.

Sample call numbers that include container

ADE 11 – Marie, no. 2 (C size)
PGA – Schulz, F.G.–Stuttgarter Bilderbogen
(B size)
FP – XX – S354, no. 3 (D size)

NOTE: The size of the container
only offers a general approximation of the size
of items contained within the container. The
size of items in the container can sometimes
be substantially smaller than the dimensions
of the container itself.

Container Designation Type of Container Size of Largest Mat, Folder, Sleeve
or Item the Container Holds
AA box 11 x 14 inches or smaller
A box 11 x 14 to 14 x 18 inches
B box 14 x 18 to 20 x 24 inches
C (except posters) box 20 x 24 to 22 x 28 inches
D (except posters) map case drawer 22 x 28 to 28 x 40 inches
E (except posters) map case drawer 28 x 40 to 36 x 48 inches
F map case drawer 36 x 48 to 45.5 x 74.5 inches
Ff “other” map case drawer up to 40 x 60 inches

How do I get permission
to use an image found through the catalog?

Rights assessment is your responsibility.

The Library of Congress can neither grant nor deny permission
to use images, as it does not own the rights
to most images in its holdings. The Prints & Photographs
Division attempts to provide known information
about the rights to images.
Whether or not
you can use an image is partly determined
by what you intend to do with it, however,
and rights to many images found in the Prints & Photographs
Online Catalog have not been individually

Finding Out About Image Rights

There are several online sources of information
that may indicate the rights status of an image.

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February 17, 2010