Childrens Illustrated Encyclopedia

405

Digital photography

a digital camera does not use film at all.

instead, it contains a light-sensitive image

sensor—a chip made up of

millions of tiny silicon

photo diodes, each of

which records the

brightness and

color of the light

falling on it when

the picture is

taken. the

picture

information is

translated into

digital data and

stored on the camera’s

memory card, from where it can

be seen on the camera screen, or

downloaded to a computer, or printed.

Developing anD printing

Until recently, every picture was taken using film. When light

enters the lens and strikes the film, each grain of light-sensitive

silver on the film is subtly changed by the light, and an invisible

image is recorded. the film must be processed

before the picture can be seen. it is immersed

in a bath of chemicals called developer. this

turns the exposed silver salts into silver

metals. the developed film is then washed

and “fixed” to create a negative or

transparency that is no longer

affected by light. in a darkroom the

image is enlarged by projecting it on to

light-sensitive paper, which in turn must

be developed to make a print.

Find out more

Cameras

Color

light

Movies

television

digital and film in close-up

Both digital and film images are made up of tiny

blocks of color, so small that they are normally invisible

to the naked eye. however, it is possible to see individual

pixels when a digital photograph is enlarged on screen

and to see separate grains when film or a photographic

print is viewed under a microscope or magnifying glass.

Photos can be

viewed immediately

on the camera’s

LCD (liquid crystal

display) screen.

Laptop computer

Photo-management

software

CaMera phones

almost all new cell

phones have built-in

digital cameras,

capable of taking

photographs and

recording short video

clips. Both pictures

and movies can be sent

immediately to other

cell phones, the internet,

or transferred wirelessly

to tvs, computers, and

printers. as image quality

improves, many people may

choose to use a single device

to combine the functions

of a phone, camera, video

camera, and music player.

On a black-and-white negative strip,

bright areas of an image appear dark

and dark areas appear transparent.

An exposed roll of film

is soaked in developing

chemicals in a

lightproof canister.

A darkroom enlarger shines light

through a negative and projects

an image on to light-sensitive

photographic paper.

Timer

A digital image enlarged until it

becomes “pixelated”

The exposed print is developed and fixed

in the same way as film.

Film grain magnified until it

becomes visible

Film

Lightproof

canister

Mini tripod

Connection cable

photography

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