The science behind developing pictures.
When you click the shutter button on your camera, the shutter opens for a fraction of a second, allowing light rays to penetrate through the aperture and lens. A latent image is formed by visible energy reflected off the objects in your viewfinder.
Light rays rearrange silver halide crystals in the emulsion layer of the film.
When the film is put into developer, the developer chemically reacts with the light-struck silver halide crystals, turning them black. After the film is rinsed, fixer is then used to remove the crystals that were not exposed to light.
What is left is a negative, areas where the most light struck are the darkest, and areas where the least light struck are the lightest.
Light is then passed through the negative and onto photographic paper, which is also light sensitive.
The exposure of the negative onto the paper is called printing.
In color film, instead of just one emulsion layer, there are several different layers, each corresponding to a different color.
Black & White Development Step-By-Step Process
- 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.
- 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.
- 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.
- 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.
Here are the steps in developing the color print paper after it is exposed:
Color Development Step-By-Step Process
- The latent-image sites are developed, and oxidized developer molecules combine with the color-forming couplers to create a silver image and a dye image. The reaction is stopped by a washing step.
- The silver image and any remaining unexposed silver halide is removed in a combined bleach-plus-fix solution (called the BLIX).
- The print is then carefully washed to remove any residual chemicals.
- The print is dried.
My Developing Process
I decided to use a homemade developing and stop solution for my first time developing pictures.
I made the developing solution by mixing
- 12 oz water
- 5 tsp instant coffee crystals
- 3 1/2 tsp washing soda
- 1/2 tsp vitamin c powder
For the stop solution I mixed
- 300 ml water
- 7 1/2 ml lemon juice
In total darkness, take the paper out of the camera and place it in the developing solution.
After 2 minutes, using a red light, check for an image appearing.
When it looks ready, take the photo out with kitchen tongs, and put it in the stop solution for 30 seconds.
Rinse in plain water and leave to dry.
Scan the image and use Photoshop to invert from a negative to a positive.