Tuesday, April 21, 2009

Black and White Photography Questions

1. An optical element (the lens), a chemical element (the film), and a mechanical element (the camera body).

2. A manual single-lens-reflex (SLR) camera: a camera where the photographer sees exactly the same image that is exposed to the film and can adjust everything by turning dials and clicking buttons. It uses no electricity.

3. To increase or decrease the amount of light passing through the lens, you have to change the size of the aperture -- the lens opening. This mechanism works the same way as the iris in your eye -- it opens or closes in a circle, to shrink or expand the diameter of the lens. When the lens is smaller, it captures less light, and when it is larger, it captures more light.

4. The length of exposure is determined by the shutter speed. Most SLR cameras use a focal plane shutter. This mechanism is very simple -- it basically consists of two "curtains" between the lens and the film. Before you take a picture, the first curtain is closed, so the film won't be exposed to light. When you take the picture, this curtain slides open. After a certain amount of time, the second curtain slides in from the other side, to stop the exposure.

5. You have to balance film speed, aperture size and shutter speed to fit the light level in your shot.

6. 100 ISO film, for example, is optimal for shots in bright sunlight, while 1600 film should only be used in relatively low light. The ideal exposure depends on the size of the light-sensitive grains in the film. A larger grain is more likely to absorb light photons than a smaller grain.

  1. In the first step of processing, the film is placed in developing agent that is actually a reducing agent. Given the chance, the reducing agent will convert all the silver ions into silver metal. Those grains that have latent-image sites will develop more rapidly. With the proper control of temperature, time and agitation, grains with latent images will become pure silver. The unexposed grains will remain as silver-halide crystals.

  2. The next step is to complete the developing process by rinsing the film with water, or by using a "stop" bath that arrests the development process.

  3. The unexposed silver-halide crystals are removed in what is called the fixing bath. The fixer dissolves only silver-halide crystals, leaving the silver metal behind.

  4. In the final step, the film is washed with water to remove all the processing chemicals. The film strip is dried, and the individual exposures are cut into negatives.
8. The negative of the original image, photographic paper, and gelatin.

9. Photographic paper?

No comments:

Post a Comment