Taylor Made: Overexposure
It has become apparent that we are in the mild winter that cycles through the prairie every few years. Regardless, in the spirit of the typical below-zero stints we see here, I will take a look at how extreme cold (and other distress) affects camera film.
Film is made from polyethylene (PE) sheeting coated with a gelatin solution which carries light-sensitive silver halide particles. Light passes through the lens, which brings the image into focus over a certain distance (remember calculating focal points in physics?), and through the aperture, which controls how much light actually enters the camera. Similar to how a periscope works, the light then reflects off a mirror to reach the viewfinder, giving a preview of how your photo will look. When the shutter is activated, the mirror moves, allowing light to hit the film at the back of the camera. The temporary diversion of light means that in the instant the shutter is open, you only see black in the viewfinder. Light on the film’s coating causes a chemical reaction that bonds exposed particles together.
The reacted particles turn black and thicken according to duration of exposure. Black and white negative film has a single emulsion layer, or layer containing particles, while color negative film has three (RGB). Essentially, the negative of the image is recorded on the film, with more light producing thicker corresponding black areas. For RGB film, the reacted particles of the corresponding color blacken, leaving the other colors exposed—this is why color negatives appear in opposite colors than reality. Note that there also exists “positive” film that directly captures subjects’ coloring. To oversimplify the development process, unreacted silver halides get washed away during a series of chemical baths. For negatives, the image is reversed during the printing process, producing the original light scheme observed by the photographer.
Film can become very stiff and brittle in extreme cold, although it remains potentially impact resistant regardless. Photographers working in subzero temperatures need to be cognizant of winding their film, as rough movement could actually tear it or damage other mechanical components in the camera. While the cold typically does not alter the appearance of captured images, the film’s cooling/warming process can have adverse effects if not managed properly (beware of moisture during warming).
In contrast, prolonged heat exposure can degrade the quality of the film, altering the appearance of the final images produced. For example, in a test of 35 mm film, where one roll had been stored to standard spec and one had been kept in a hot car, the comparable photos produced showed significant differences; namely, that the heat-treated film’s images had less contrast and less saturated colors, as well as a grainier appearance. However, just as we can now achieve similar effects for fun using digital filters, this style is preferred for some artists.
One of the simplest ways to distort the appearance of a subject is to manipulate how much light hits the film, and the manner in which it hits. Freelance photographer/videographer Will Comai provided me with a few sample photos that demonstrate the effects of manipulating the amount of light captured in a shot. Note that although these were shot digitally, they support the same effects as analog images would. Each photo shown was taken using long exposure, meaning that the shutter was kept open for a long duration (i.e. on the scale of seconds instead of fractions of a second). With the shutter kept open, Will could implement techniques to distort the captured image, such as deliberately moving the camera to manipulate how the light would be recorded.
Even with the camera kept completely still, altering a single factor (like shutter speed) during a shoot would produce significantly different images. The method of manipulating factors in art to produce different works is reminiscent of the optimization process engineers go through in designing a product, in which they deliberately change individual factors and analyze the net effect. While the realms of engineering and art may feel like opposite ends of the spectrum, I find that these perceived boundaries often overlap.