Making Chemical Maps
Staff scientist Sam Webb places a sample into an X-ray absorption experimental station at the Stanford Synchrotron Radiation Lightsource (SSRL). This endstation was used to take data for a NASA-funded experiment looking at bacteria found in Mono Lake, CA that substitute arsenic for phosphorous within their DNA.
This setup is also used by visiting researchers investigating environmental contamination and other studies that require high-resolution chemical mapping—for example, finding ways to clean up toxins in soil by first precisely identifying them, or understanding disease by pinpointing harmful compounds in samples of brain tissue.
The shot: Canon 5d MkII, 24 mm f/2.8L; 1/40 sec exposure, ISO 400. Oftentimes a scientist will wear the perfect clothes by complete coincidence… case in point here with Sam’s horizontal orange and brown stripes. The acrylic box on the right (filled with helium—air interferes with X-rays) I highlighted from below with a red gel on a 600 w/sec monobloc strobe (slave mode), positioned beneath the table and pointed at the floor. Sam is illuminated by a gridded Speedlite 550 on a Gorillapod, camera right, triggered by a Pocket Wizard II.
One of the first things I do when setting up a shot like this is turn off the overhead lights, and turn on any local point sources or indicator lights, which makes the shot more dimensional to my eye. Guides a viewer’s attention in a more interesting way. All of the light shining on the sample Sam’s holding comes from the twin fiber optic lights arcing like antennae from the black box in the background. Fiber optic lights are plentiful in the experimental hutches, and I always make sure to have them on. Same is true for a previous post, A Tale of Two Light Sources.