The document discusses the Library of Congress' efforts to digitize its photographic collections from the 1930s-40s, including the Farm Security Administration collection. It describes the deterioration of the original nitrate negatives over time and the need to digitize them for preservation. The LOC developed an automated system using a camera, XY table, and custom software to digitize the large FSA collection at a high resolution while maintaining the integrity of the original images. The digitized files are stitched together using image recognition software and made available online, restoring access to these important historical photos.

1. EVERYTHING OLD
IS NEW AGAIN
(AND AGAIN)
Digitizing
Negative
Collections in a
New Way at the
Library of
Congress
Taren Ober Ouellette
Digital Conversion Specialist
Library of Congress, Prints & Photographs
Division
__________

2. THE YEAR IS 1994 AND THE LIBRARY OF
CONGRESS IS BEGINNING TO DIGITIZE
ITS COLLECTIONS…

3. IN THE MID-1990'S, THE LIBRARY OF
CONGRESS WEBSITE AND ITS DIGITIZED
IMAGES LOOKED A LITTLE MORE LIKE THIS:
Tiff images are approximately 251KB!

5. FARM SECURITY ADMINISTRATION -
OFFICE OF WAR INFORMATION (FSA,
OWI)
• Government-funded photographic
documentary project
• Encompasses the Great
Depression era through the
beginnings of WWII
• Shows rural scenes, urban scenes,
factory workers, etc.
• Some examples of the famous
photographers who contributed to
the work:
o Dorothea Lange
o Walker Evans
o Gordon Parks
o Marion Post Wolcott

6. Destitute pea pickers
in California. Mother
of seven children.
Age thirty-two.
Nipomo, California.
Photo by Dorothea
Lange, 1936.
//hdl.loc.gov/loc.pn
p/fsa.8b29516
Toward Los
Angeles,
California. Photo
by Dorothea
Lange, 1937 Mar.
//hdl.loc.gov/loc
.pnp/fsa.8b3180
1
Floyd Burroughs,
cotton sharecropper.
Hale County, Alabama.
Photo by Walker
Evans, 1936.
//hdl.loc.gov/loc.pnp/
ppmsc.00244
Washington, D.C.
government
charwoman. Photo
by Gordon Parks,
1942.
//hdl.loc.gov/loc.pn
p/ppmsca.05809

7. DEGRADATION OF NEGATIVES
• Deterioration despite
proper handling and
storage
• Symptoms include
• Vinegar syndrome
• Channeling
• Bumpiness/Waviness
• Brittleness
• Flaking
• Inevitable for all negative
collections from the same
era
•Digitization will serve as
form of preservation

8. MATHEMATICAL AND VISUAL
ANALYSIS OF NEGATIVE MATERIALS
• Sampling rate and resolving
power measured for both safety
and nitrate materials
• Film materials/Camera
lenses/Film brands all contribute
to difference in grain quality of
negatives
• Visual checks also performed
• Nitrate film – 2800ppi
• Safety film – 3200ppi
Automated SFR Analysis
www.digitizationguidelines.gov/guidelines/FADGI

9. TRADITIONAL COPY STAND SET-UP
 Traditional copy stand table
concept
 100mp camera
 Tethered capture
 Glass film-holder
 Custom XY table
 Equipped for transmissive
materials

10. INTRODUCING THE XY TABLE
 Grooves in metal are pre-set
locations (détente bars) designed
for each film format and resolution
 Glass film holder sits above a
bellows or accordion-like table
 Operator moves film holder platen
to each position and shoots each
capture individually
 Pre-set locations include enough
overlap of detail between each
quadrant for successful stitching
later

11. X - AXIS
Y - AXIS
4
CAPTUR
ES

12. THE SIFT ALGORITHM
• Scale-Invariant Feature Transform
• Algorithm used to stitch images in most stitching programs on the market
• Programs usually offer preset methods of stitching (ex. Collage, Panoramic,
Auto Blend, etc.)
• Involves warping and blending of pixels
• Some argue that any manipulation of pixels is too much and choose to
display images in parts instead

13. Family of day
laborer living in
Arkansas River
bottom at
Webbers Falls,
Oklahoma.
Muskogee
County. Photo by
Russell Lee, 1939
June.
//hdl.loc.gov/loc.
pnp/fsa.8b22077

14. STITCHING ERRORS
Classic “stair-step”
error
Stitching program confuses
similar data points on target
“Squished” effect Missing capture
Untitled]. Unknown photographer.
Date between 1935 and 1942. //hdl.loc.gov/loc.pnp/fsa.8b13737

15. 2018 Image 1994 Image
[Untitled]. Unknown photographer.
Date between 1935 and 1942. //hdl.loc.gov/loc.pnp/fsa.8b20192

16. WHERE DO WE GO FROM HERE?
Taren Ober Ouellette
Digital Conversion Specialist
Library of Congress,
Prints & Photographs
Division
tobe@loc.gov