Beginning Level Activity
1. Display an image of Dr. John Murray's photograph The Emperor's Private Mosque in the Marble Palace, Agra Fort, India. Explain that this is a paper negative that was created with a camera. Use the Questions for Teaching for this artwork to get students to look closely at the image. Explain that students will create a simple camera to understand the type of basic tool that artists use to make photographs. Explain that the paper negative was created in a similar way to the types of activities they will be doing. As a class, explain that light travels in a straight path and that humans learned to use light to create images on paper. Explain that the word photograph means "to write with light," and that camera means "room." Therefore, when we take a picture with a camera we are capturing light in a small dark room.
2. Look at early photographs in negatives and prints such as cyanotypes, daguerreotypes, ambrotypes, and salted-paper prints. Show students the following examples of photographs printed on metal, glass, and paper. (Find more examples by browsing the list of types of photographs on the Explore Art section of this Web site).
• Metal: The United States Capitol, by John Plumbe, Jr (daguerreotype)
• Glass: Couple at Niagara Falls in Waterproofs, attributed to Henry Hollister (ambrotype)
• Paper: View of the Boulevard of Paris, by William Henry Fox Talbot (salt print)
Discuss how a camera was used to expose either glass, metal, or paper coated with photosensitive chemicals (chemicals that react to light), in order to create these images. Compare how the images look on the different types of material. The images on metal and on glass are sharper than the image on the paper photograph, which is soft and slightly blurred, with less detail visible. Explain that a negative is the image that is made with the camera, and the print is the positive image or opposite of the negative. You may have students watch the videos Photography: The Wet Collodion Process and Early Photography: Making Daguerreotypes. This will help students understand the complexity of early photographic processes. Explain that technological advances in the past 100 years have made it easier for us to use cameras and to make negatives and prints.
3. Students will create pinhole cameras. The technology for a pinhole camera is similar to the technology seen in the Making Daguerreotypes video. First, you will need to spray paint black on the inside and outside of empty cardboard oatmeal canisters. Spray paint works best for an even, thick coat of paint so that no light can come in from the sides of the canister.
• Give each student a pre-painted oatmeal canister, a piece of wax paper, a rubber band, a piece of black paper, and masking tape.
• With a pin, help students poke a hole in the center of the bottom of the canister.
• Students will center the wax paper over the top of the can, wrap it around the sides, and secure it with a rubber band.
• Then students will wrap the black paper around the perimeter of the canister and align the edge of the paper with the bottom of the canister. At the top of the can, the paper should extend past the wax paper top by at least two inches.
• Secure the paper to the can with masking tape.
4. Take the pinhole cameras outside or around the classroom. Point the bottom of the canister towards an object, person, or place. Have the students look into the top of the canister and cup their hands around the edge to keep all the light out. Ask the students the following questions: What do you see? How does the image compare to the way it looks without the camera? How does the image change if you move closer to the object? How does it change if you move farther away? The students should see the image on the wax paper screen, but it will be upside down. As they move closer and farther away from the object, it will change in focus and size.
5. Explain to the class that light always travels in a straight path. When they look at an object through the simple camera, it is upside down because the light that hits the top of the object has to pass through the pinhole and will come out on the other side (on the screen) in the opposite position. Have students fill in Illustration #1 in the handout Light Waves and Lenses Illustrations to demonstrate the principle. Have students draw in the lines that represent the light waves, by following the diagram.
Intermediate Level Activity
6. Pass out small magnifying glasses to the students. Have each student place the magnifying glass in front of the pinhole in his or her camera and look at the image on the wax paper. Ask students how this image looks, compared to the image they see when they don't use the magnifying glass.
Explain that the magnifying glass functions as a convex lens. When light passes through the lens, the light is refracted or bent by the curved glass. This forces the light waves to move closer together as they pass through the pinhole or the focal point. This function of a lens is what allows photographers to focus on images at a variety of distances. When passing through a convex lens, the light waves are bent towards the optical center of the lens, causing them to converge on the focal point in front of the lens. The relative position of the object with respect to the front focal point of the lens determines how the object is imaged. If the object is beyond twice the length of the focal point, then it appears smaller and inverted (see Illustration #2 on the Light Waves and Illustrations handout). If the object is closer to the lens than the focal point, the image appears larger and upright (see Illustration #3 on the handout).
Advanced Level Activity
7. Students will make photographs with their pinhole cameras. They may follow the directions below.
Preparation
• Have each student identify an object to photograph. Choose objects that do not move.
• Instruct students to cover the pinhole with a piece of electrical tape.
• They should also remove the paper sleeve and wax paper from the camera.
• Hand out the lids for the canisters.
• Have each student paint the lid of their canister with black paint.
• Set aside to dry.
• Have students gather two flat objects to place next to their cameras to keep them from rolling around.
• Ask students to set cameras up near the object they will photograph.
Exposure
• Hand out the photosensitive paper in its package. Inform the students that they will quickly take out the paper, place the blue side against the top of the canister, and then cover the back with the lid. Give students about half a minute to do this. You may want to give them regular pieces of paper to practice with one or two times before using the photosensitive paper.
• Once the lids are in place, have each student secure the camera with the flat objects next to it. Students will then remove the tape from the pinhole for five minutes, replacing it when the time is up. Students may also want to practice this with the regular paper first to get the hang of it before using the photosensitive paper.
Developing
• Students should take their cameras to a sink and fill the sink with cold water. They will quickly remove the lid and paper from the camera and submerge the paper in the cold water for about four minutes. Remove the wet paper and allow it to dry. Students will have a negative image of their subject.
8. Divide the students into pairs. Each pair should compare their negatives to the actual objects they photographed. Which types of surfaces on the object created specific tones or colors in their negative? Pairs should chart their comparisons and share their findings with the class.
9. Students will use this information to experiment with taking photos of various objects that have reflective and dull surfaces. Repeat the exposure process in Step 7. Hand out journals and have students record results.
10. Display the reproduction of the photograph by Dr. John Murray. Discuss how that negative is similar to or different from their photographs. Ask students to identify which areas of the mosque might have had reflective or dull surfaces, based on their observations of their own negative photographs.
11. Students will then take photographs using a lens with their pinhole cameras. Have students mount mini magnifying glasses to their cameras with tape. Students should hypothesize about how the lens will effect their photograph, based on their knowledge of the characteristics of light waves. Repeat the exposure process in Step 7. Have students record their hypotheses, observations, and findings in their journals.
12. Students can also experiment by placing an object inside the canister in front of the paper. After they expose the object and paper, they will see a silhouette of the object on the paper. Areas around the object will be fuzzy. Explain to students that the fuzzy areas were created as light waves were obstructed by and diffracted around the object.
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| Emperor's Mosque, Sr. John Murray, 1857–1860 |
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