Graphics Programs Reference
In-Depth Information
But where did the term
pixel
come from? Pixel
is an abbreviation for
picture element
. The word
was coined to describe the photographic ele-
ments of a television image. In 1969, writers for
Variety
magazine took pix (a 1932 abbreviation of
pictures
) and combined it with
element
to describe
how TV signals came together. There are even
earlier reports of Fred C. Billingsley coining
the word at NASA's Jet Propulsion Laboratory
in 1965. Although the exact origins of the word
may be disputed, its meaning is not. The word
pixel
quickly caught on, first in the scientific com-
munities in the 1970s and then in the computer-
art industry in the mid 1980s.
A close-up of TV picture elements, or
pixels
.
So What Are Megapixels?
When you shop for a digital camera, you are
bombarded with talk of megapixels. Consumers
are often misled about what megapixels are and
how many are needed. A
megapixel
is simply a
unit of storage, whether internal or on a remov-
able card. A megapixel is one million pixels and
is a term commonly used to describe how much
data a digital camera can capture. As with your
car, just because your tank can hold more gallons
of gas doesn't mean it's more fuel efficient or bet-
ter than your friend's car.
The red circle shows an enlargement of the image. Notice
how you can see actual pixels when you increase the magni-
fication of an image. These squares of light are the building
blocks of all digital photos.
For example, if a camera can capture pictures at
3000 × 2400 pixels, it is referred to as having 7.2
megapixels (3000 × 2400 = 7,200,000). If you were to print that
picture on paper at 300 ppi (pixels per inch), it would roughly be a
10" × 8" print. Professional photographers may need more pixels
than this, but a consumer may not. It all depends on how the pix-
els are meant to be displayed or printed.
The more pixels you capture, the larger the image is (both in disk
space and potential print size). Consumer usage (such as email or
inkjet prints) is less demanding than professional usage (such as
art topics or magazines). Professionals need more megapixels than
consumers; hence, high-end cameras cost more because they are
targeted at people who make money by taking photos.
Digital cameras
use card-based
storage, like this
Secure Digital
card, to hold the
captured pixels.
