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Collection Carnegie Survey of the Architecture of the South

Technical Information

What Was Digitized

All photographs found for the CSAS collection at the Library of Congress were digitized, including images that show similar views. These variants offer insight into Johnston's photography methods and the work of a professional photographer. They illustrate how she tried different framing and lighting to compose a scene for best effect. See, for example, the Gibbes William House in Charleston, South Carolina.

Most of the digitized images are from 8x10 inch safety film negatives, although some are on an earlier kind of stock called nitrate film. The Library digitized these large format negatives because they are the first generation image--the film that was in the camera. The first generation image provides the full frame (uncropped) and the sharpest detail compared to subsequent prints. One drawback of viewing negatives is that they do not represent the photographer's final product--the prints made for display or publication, with special cropping or tonality adjustments.

Johnston's original film negatives date from an era when the plastic base tended to shrink over time. This inherent chemical deterioration causes the emulsion image layer to buckle or channel. Most of the deterioration in the CSAS negatives appears in views of Virginia and Maryland. For example, channels are visible as white lines in this view of a country store. For negatives with significant channeling or spots, a print was also digitized to provide a more legible image. Approximately 250 prints supplement the images from deteriorating negatives.

No negatives were available to digitize for approximately 500 images due to several situations. Some negatives were recorded in the card index but retained by Johnston and not found after her death. Other negatives were discarded in the 1950s due to severely deteriorated condition. And, some of the negatives that have survived could not be digitized because they have deteriorated too far to handle safely.

Library staff searched for an alternative representation for images listed in the Carnegie Survey card index that lack negatives. The priority for selecting these approximately 350 substitutes for the negatives was:

  • film preservation transparency (called an interpositive) made for the Library in the 1980s for negatives that showed signs of deterioration (8x10 inches)
  • print made by Johnston or Library of Congress (sizes vary, 8x10 to 16 x 20 inches)

The catalog records identify what was digitized in their call numbers or notes:

  • Negatives have the phrase "digital file from original negative" with the digital file identifier "LC-DIG-csas" and the call number "LC-J7" (approximately 6,600). Example: Mountain Home, with Johnston’s shadow.
  • Interpositives have the phrase "digital file from interpositive" with the digital file identifier "LC-DIG-csas" and the call number "LC-J7-T" (approximately 225). Example: Debtor's Prison, VA.
  • Prints have the phrase "digital file from print" with the digital file identifier "LC-DIG-ppmsca" (approximately 350) Example: Resurrection Manor, MD.

For the state of Mississippi, the Library received no negatives. We found 18 prints made by Johnston among her printed architectural photographs that had CSAS negative numbers on them. Most were 8 x10 inch prints, and a few were in the 16 x 20 inch exhibition size. A donation in 2011 added another 37 8x10 inch prints. As a result, 55 of the 75 Mississippi views taken for the CSAS are now available.

Approximately 280 of the online catalog records have no image. The Library of Congress does not have a negative, interpositive, or print, although there was an entry in the card catalog. The records are in the online catalog to indicate the full scope of Johnston's survey work. If images are found at other public institutions, we will try to link to them to fill out the representation of the survey. The phrase "no image in LC" identifies these negatives.

Specifications

Uncompressed TIFF Images (file names ending in u.tif)

Spatial resolution:
5,000 pixels on the long side with the short side scaled in proportion (17-20 megabytes)
Tonal (pixel depth) resolution:
8 bits per pixel (grayscale)
Image enhancement:
None
File format:
Tagged Image File Format (TIFF) ver. 6.0
Compression:
None

Highest Resolution Archival TIFF Images (file names ending in a.tif)

Spatial resolution:
10,000 pixels on the long side with the short side scaled in proportion (approximately 160 megabytes)
Tonal (pixel depth) resolution:
16 bits per pixel (grayscale). Note: Some older versions of image viewers and editing software cannot handle 16 bit images.
Image enhancement:
None
File format:
Tagged Image File Format (TIFF) ver. 6.0
Compression:
None

Compressed Service Images (file names ending in r.jpg and v.jpg)

Spatial resolution:
640 pixels on the long side with the short side scaled in proportion (40-50 kilobytes for r.jpg). Also, 1024 pixels on the long side with the short side scaled in proportion (90-100 kilobytes for v.jpg)
Tonal (pixel depth) resolution:
8 bits per pixel (grayscale)
Image enhancement:
Mild sharpening
File format:
JPEG
Compression:
Compressed to yield an average compression ratio of 10:1

Thumbnail Images (file names ending in t.gif and t.tif)

Spatial resolution:
150 pixels on the long side with the short side scaled in proportion (approximately 20 kilobytes); made from the r.jpg files
Tonal (pixel depth) resolution:
8 bits per pixel (grayscale)
Image enhancement:
Mild sharpening
File format:
Archived copy: TIFF-Tagged Image File Format
Online copy: GIF-Graphics Interchange Format
Compression:
Archived copy: Uncompressed
Online copy: Compression native to the GIF format
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