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Thomas C. Lytle
Visual Communications
November 3, 1998
EECS 498
More
Colors
One of the most explosive markets in the past three years has been the growth of
the imemet. It has been said that a new domain name is purchased abom every two
minmes. This equates to abom 260,000 new web sites each year! Bm something is
missing! Did you know that even though most color monitors can display over 16
million colors, only 216 colors appear similar when viewed with browsers on differera
platforms? To make matters even worse, most of these colors don't even match. And
when you try printing these colors on a color printer, your choices are even more limited.
In a few years, personal digital assistants such as the Palm Pilot will most probably
incorporate color into their displays. As the years go on, people will demand more and
more from products. The time has come to figure om exactly what can be done abom this
color issue.
To begin, let's familiarize ourselves with some basic knowledge. Computer
monitors use groups of pixels to display colors. Each group of pixels is made up of
three differera color pixels. There is a Red pixel, a Green pixel, and a
Blue pixel. By mixing the intensity of these pixels, computers can display many
differera colors. This system is know as RGB for Red Green
Blue. And computers use this model because the human eye works very similarly to
this model. Both monitors and televisions emit light.
On the other hand, most printed images absorb light. Thus primers and priming
presses use the CMYK color model when priming in full color. It stands for
Cyan (a blue color), Magema (the closest thing to red), Yellow,
and blacK. These colors were chosen long ago because they do a good job at
represeming what we see in the real world. Each of these colors is considered a
'Reflective' color. When light from the sun or a light bulb hits an object such as green
grass, all of the light waves are absorbed by the grass except the green waves. These
waves are reflected and picked up by our eyes. The CMYK colors work much the same way.
A page primed with Yellow ink absorbs a lot of the cyan and magema light rays but very
little yellow light waves. Thus, what you see is yellow page. A page printed with both
yellow and cyan appears to be green (yellow and blue make green). The black ink absorbs
all visible light waves. The important thing to understand is that this is so differert
from how a monitor works. On a monitor, light is being emitted through the screen
directly imo our eyes, whereas with prim, the light can only be absorbed and reflected.
This is one of the big deals about color on the Intemet. Even more surprising is
that computers with different operating systems or even different programs imerpret RGB
differently. This means that a red color on one computer my appear to be violet on
another computer. We cannot accept this any longer. A standard method needs to be
developed to incorporate any and all kinds color methods. This standard method is
curremly lacking in our society.
Additional Information
Computers use bits (derived from the word Binary digit) to think, store, and
transport information. A bit is much like a switch and can be either 1 (on) or 0 (off). By
combining many switches together, we can create more combinations. For example, with
one bit, we can represent White as 0 and Black as 1. We have no other options available.
But, by using two bits, we have more options. White is 00, Red is 01, Blue is 10, and
Black is 11. And we can go on and on. With 4 bits we can represem 24 = 16 colors.
Curremly, computers use 24 bits to display a multitude of colors. Each RGB color red,
green, or blue, uses 8 bits to represem how much of that color to emit. A value of 0 red
means that no red light is being emitted. A value of 256 red means that a full blast of red
is being emitted. Furthermore, a complete value of (256, 256, 256) will give you white
light.
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