The glass negative (Library of Congress) from which this image, never published as a stereocard, was created is severely degraded, with sections of its emulsion missing. Furthermore, due to the long camera exposure time and the photographer's inability to control the movement of the crowd, some of the people in the foreground are visible as secondary "ghosted" images.
Most of these defects in the image
were digitally remediated in order to highlight the 3D effects of the anaglyph and the animation on this page.
While not apparent here, some who have investigated this image and the other two views that Gardner made at the same time have identified what may be President Lincoln in the background. More information about this may be found here and here. A more widely accepted view of the president on the speaker's platform may be seen here.
If you have red/cyan 3D glasses, click on the stereo pair above to see its anaglyph.
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