How does Photography Work

HOW DOES PHOTOGRAPHY WORK?

DIGITAL PHOTOGRAPHY 1

Lens or pinhole Lightproof Box
Object
Light Sensitive
Paper

THE LENS

• The device that focuses the light into the lightproof box
• Can be a group of glass elements held together inside a tube
• Can be just a pinhole
• Places light onto the light-sensitive paper inside the lightproof box

EXPOSURE

Exposure - The image formed by the light on light sensitive paper, film,
or digital

In Early Cameras:
• Used a lens cap to let light in or keep light out

Today:
• Uses a shutter

• A mechanical door that opens and then closes either inside the
lens (glass in a tube) or in front of the light sensitive paper

LIGHT SENSITIVE MATERIAL

Film - Thin layers of microscopic grains of silver salts, silver chloride
and/or silver bromide suspended in gelatin

Digital - Silicon based chip
- Transferred to computer and processed using software

FILM

1. Processed in a developer
- turns salts that have been exposed into metallic silver

2. Unexposed salts are removed by the fixer
- results in a negative (light objects are dark and dark objects
are light)

3. Make print
- negative projected onto black and white photographic paper,
reverses tones back to light and dark of the original