About the Scans
The Hasselblad 500c is a Swedish designed medium format single lens reflex camera that was first introduced in 1957. The camera was fitted with a Carl Zeiss lens with a built in leaf shutter. This camera was renowned for its clarity. The camera that was taken to space was modified to make it lighter and sent up on the first Mercury mission. The consumer version was first carried to space by astronaut Walter Schirra when he piloted Mercury 8. It became the foundation of a line of cameras which was used by Neil Armstrong and Buzz Aldrin to record the first images of man on the Moon. The astronauts used a motor-driven Hasselblad 500EL/70 (70mm film back) Data Camera fitted with a reseau plate and a Zeiss Biogon 5.6/60 mm lens. Traditional lubricants were replaced by a low friction alternative and metal plating was used instead of the standard black leatherette covering.
The Mercury photography scans were acquired by Johnson Space Center. Rob Ingram was responsible for the scanning and Mary Wilkerson validated the originally named/cataloged film. The negatives were scanned with an Oxberry 70mm system. The Oxberry uses the Kodak HR-500 scanner, which incorporates the Kodak KLI-6013 tri-linear line sensor (one line each for red, green and blue). Dark signal correction and flat-fielding are performed automatically during standard scan operations. Scans are digitized as 8-bit numbers (DN range 0-255) per channel (24-bits total for RGB composite). The Oxberry 70mm scanner was adjusted at the factory and in-house tests indicate the geometric fidelity is within 1 part in 3000 vertically, and better than 1 part in 6000 horizontally (assuming the film is properly aligned). The scans are 4410 samples by 4600 lines, and the file sizes are 58 Mbytes.
|* These images demonstrate the image processing techniques and methods used. These sample images show how our image processing improves the visual quality of the images from the raw film scans.|
The raw frames are processed in two steps for distribution (raw scans are also archived and made available). The first step is the removal of background density (base plus fog). This background is estimated from different statistical regions outside the frame area (see figure) of each image. The second step is a simple contrast adjustment using a half percent histogram stretch for each of the red, green and blue components. In addition to the enhanced full resolution frame several reduced resolution products are also produced for distribution and making movies from the more dramatic sequences.
Why is there writing on some of the Mercury images?
Many of the Mercury images have hand written annotations on the film, and perhaps now this seems odd. Remember that the Mercury flights were engineering tests - NASA was inventing human spaceflight. The frames were marked to facilitate analysis, plain and simple. One can view the notations as dedication to the cause, a signal of the urgency to succeed.
Digital scans of flight film images (Mercury, Gemini, Apollo) in their raw (unprocessed) form are in the public domain. Please credit processed images (i.e. post scan products such as movies and enhanced images) to: NASA/JSC/Arizona State University.