When spacesuit expert Amanda Young and I were working on photographing our spacesuits for her book, she told me that a series of test x-rays had been taken of small objects such as gloves, boots, and helmets. She wanted to have a whole spacesuit x-rayed next, if it could be done. She asked my advice on how the radiologist, Roland “Ron” Cunningham at the Smithsonian's Museum Support Center, could combine a lot of small sheets of x-ray film together into one big piece.
The largest film available for x-rays is 14 x 17". I suggested that they get some 4 x8' feet foam core board, which is extremely light, strong, and stiff, and tape or tack the unexposed film onto the board. I also advised them to be sure to overlap the film at least one inch, so there would be no spaces in between any of the films.
Ron took my advice and set the film up on the foam core, with three sheets of film across and five sheets down, for 15 sheets total, which is roughly 50 x 70". Then he laid the spacesuit on top of it. The x-ray machine was raised high enough to “zap” the entire suit. After the film had been exposed, it was processed and dried before being sent to me.
My job was to scan the x-ray films to create one digital image. First, I laid out the film on the light table and made sure I lined them up correctly before I started the scanning. It was like working with a jigsaw puzzle. I used the Epson Expression 10000XL photo flatbed scanner with the transparency unit. The scanner can cover 13 x 17", but the films were 14 x 17". So, I had to make two scans of each film by scanning at one end of the film, then rotating it 180 degrees to scan the other end. After I scanned all 15 sheets like this, I ended up with a total of 30 images.
With Photoshop, I opened all of the images, rotating half of the scans to the right orientation to match with the rest, and then “stitched” them together with the “photomerge” application. Then, I started with the row of three images of the head area, stitched them together, followed by the next three images of the chest, lower abdomen, legs, and finally the feet area. Finally, I stitched the five rows of images all together into one complete image.
This process took an entire day, but it was worth it after seeing such a gorgeous result. I was excited to work on more spacesuit x-rays after that first one. These days, like many of us photographers who no longer use film to shoot images, radiologists are now using digital x-ray machines instead of film. They also have new software to put together sections of the larger object into one image without going through the tedious process I used.
--Mark Avino, chief of photographic services for the National Air and Space Museum