Sun Print Experiment
In the late 19th century, long before traditional photography was established, Joseph Nièpce began experimenting with “ways to produce an image through the action of light on photosensitive materials.”[1] Beginning in 1816, he used a silver chloride solution to make paper sensitive to the effects of light, which produced results but weren’t perfect considering that the print was too faint and would change each time it was exposed to the sun.[2] John Herschel, a British scientist, used many of the same ideas as Nièpce to develop what he dubbed a cyanotype, which similarly exposes chemicals to the sun to create a deep blue image. Even though this process didn’t completely capture what would be considered a traditional photograph, it can still be demonstrated today using simple household materials.
Instead of buying cyanotype paper from a craft store, I decided instead to make my own. The process seemed simple enough, as the only materials needed were ones most people already have at home. According to the instructions, the most important ingredient is sugar, as it “turns to carbon when heated.”[3] It was hard for me to believe that such a chemical reaction would take place with just sugar, but my mind wandered back to all the cooking shows I used to watch when I was at home with nothing to do. When a pastry chef melted sugar over a stove, it would turn a rusty brown color. Although the transformation would not be as obvious with sunlight on paper, I understood how it could work. In addition to the sugar, the only other ingredients are water and glue: water to dissolve the sugar, and glue to create a paste. I thought using white computer paper for this experiment might be problematic for a couple of reasons. First, it’s a flimsy material, which might not hold up if covered in thick paste. Second, the change in color might not be as obvious since it’s an extremely light color to begin with. Third, it seemed more interesting to experiment with different shades of paper, so I picked up light pink and light blue scrapbook paper for my sun print. By using both a warm and cool color, I would be able to see the difference between how certain shades would react when exposed to the sun. I mixed the sugar, water, and glue in a bowl using the correct ratios, applied it to strips of each kind of paper with a brush, and hung them out to dry on my balcony after the sun had already gone down to ensure that light would not affect them prematurely.
The article suggests that you heat either a screwdriver or nail over a fire and draw on the paper to reveal the color changing science behind the sugar. As instructed, I heated a screwdriver over a candle and began to draw on the paper. However, nothing happened. I could sense a bit of a transformation on the blue paper, but other than that, the changes were undetectable. Frustrated, I decided instead to use the paper as you would a “sun print” and leave it outside with stencils on top. With the remaining unaltered paper, I cut out various shapes and affixed them to my homemade cyanotype paper with tape. However, I realized that there isn’t a place in my apartment that gets direct sunlight; even my balcony has too much of an awning. Nevertheless, I decided to carry on with my experiment. I taped the paper to the railing of my balcony and left them outside for an entire day.
It had been a very sunny day, and I retrieved the paper at dusk. As I began to peel off the stencil shapes, I realized that while the blue paper had slightly darkened, the pink paper looked exactly the same. There wasn’t an obvious change to the blue paper, but you could definitely distinguish an outline whereas on the pink paper you couldn’t tell a difference at all. I predict that this has to do with the fact that darker materials are more likely to show a difference when exposed to the sun. Although this wasn’t included in the original instructions for the homemade sun print paper, some craft stores propose that cyanotypes truly take effect when placed in water, so I decided to add that step to my experiment.
Wondering if it would affect my prints, I cut the trial papers in half and submerged one part of each in water. Instead of using regular tap water, I added a generous amount of salt to each container. I knew this probably wouldn’t affect the outcome, but I figured it would be more likely for sodium chloride to react noticeably with sugar than just water would. After leaving out the submerged strips to dry overnight, I noticed that the saltwater soak didn’t noticeably affect the sun prints. I figured that nothing would happen, but I decided to try just in case and my predictions were confirmed.
Although the sun print did not work exactly as I had planned, I discovered a few aspects of photography that helped me better understand how the process works. I have always had a difficult time wrapping my head around how all the different chemicals react and capture light, but after attempting to do so myself, I realize how specific the circumstances need to be to capture a proper photograph. For example, using a darker base will help to speed up the process and create more prominent results. If direct sunlight isn’t available, the photograph will need to spend significantly more time exposed to some sort of UV light. While it may seem obvious to some, I couldn’t comprehend how certain chemicals would darken when exposed to light but understanding how sugar reacts when boiled urged me to make the mental connection between sugar in baking and sugar in photography. While my sun prints may not have been as successful as possible, the fact that they even worked at all astounds me, and it just emphasizes how quickly sugar on a dark surface will react with the sun considering that the prints never received extremely direct sunlight.
[1] Marien, Mary Warner, Photography: A Cultural History (Pearson Education Inc., 2015), 10-1.
[2] Stulik, Dusin, Kaplan, Art, Salt Print (J. Paul Getty Trust, 2013), 5.
[3] David, Isaiah, How to Make Thermal Paper, http://www.ehow.com/how_2063489_make-cyanotype.html.