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Sun printing is a process by which the light from the sun is used to help develop an image. Have you ever left a few pieces of paper in direct sunlight for a period of time and, when rearranging them later, noticed that the color of the pages on the top of the pile is different from those on the bottom of the pile? Perhaps, if the pages were scattered a bit, the bottom sheets even seem to show the shadow of the top sheets. Maybe you have noticed a similar effect when taking down items that had been posted on a bulletin board for a long period of time. If this sounds familiar to you, then you are already familiar with the basic concept behind sun printing.
There are a few different technical processes for sun printing which create images that are a bit more specific and intended than the blurred shadow of an overlaid piece of newsprint. One of the most common forms of sun printing is a process similar to that which is used to develop photographs. This process relies on the use of gelatin, a dilute solution of potassium dichromate, and exposure to sunlight. The result of this process is a negative plate that can be inked and used in a hand press to make as many prints as are desired.
It is also possible to take a negative of a photos, place it over a sheet of black and white photographic paper, and develop the image via sunlight exposure. This process can take anywhere from a few minutes to a few hours. The defining factor is the type of photographic paper that is being used. Once the image is produces on the paper, it must be fixed and washed according to standard photographic procedures.
Yet another type of sun printing is the process by which cyanotypes are created. To create a cyanotype, you must treat a piece of paper with a solution of potassium ferricyanide and ferric ammonium citrate. Then place an object on top of that paper. It is preferable for the object, such as a leaf or piece of lace, to be rather flat. When the paper, with the object on time, is exposed to sunlight, the UV light from the sun will cause a chemical reaction that will result in a print of the object which was placed on top of the paper. The image can be fixed to the paper by washing it with water.
@snickerish - I don’t know if there is better sun printing paper or not but I am assuming so because the sun printing paper that I have mostly seen is made to be used by adults or by children because as you could imagine this paper makes for a great science lesson!
I would highly suggest it. Just from reading the article I see that you could incorporate math, science and graphing components into a lesson on sun paper.
You could graph to see whose sun paper took the longest to create an image, you could find out what length of time made for the best images when the sun paper was left in the same place...
guess you can tell at this point I work in a school! But still something fun to do with kids at home, and I have seen kits that help you have all the components for a successful printing session to make it an easy activity as well.
I have always loved taking pictures, but I have never actually taken a course in which they teach you how to print your own pictures via a dark room or via sun printing.
And actually the only way I thought there was to printing a picture was via the dark room! So it is interesting that the two extremes of light and dark are where the transformation takes place.
But seeing as how this might be possible with just trying some trial or error after reading this article or reading a short how-to on sun printing I might have to try it.
Does anyone know if some sun printing paper is better than others?
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