Page 64 - DCAP303_MULTIMEDIA_SYSTEMS

Multimedia Systems

notes 3. your monitor
There are several factors that may cause colour distortions:
• Old monitors can be burning out. For example, the mechanics that generate the colour
green may be weakening.
• Cheap monitors deliver terrible colour. You get what you pay for. A monitor that is of
lower cost may have poor colour accuracy.
• Anti-glare screens lower the radiant emissions and this affects the colours generated
on your monitor. Colours will appear darker than the actual colour and you may see a
grey haze over the whole monitor screen (similar to how colours appear when wearing
sunglasses). A better solution is placing your monitor away from glare sources. This
will give you better colour and optimum visual conditions. Regarding electromagnetic
field emissions, it is represented that good monitors are properly shielded and that
emissions are restrained to the sides and back. The validity of these reports is subject
to further questioning.

Therefore, the monitor can be the major cause of good or bad colour, or the monitor can be part
of the combination of several Components that creates good or bad colour. In other words, if
you have a good video card, good operating system software, and good application software, a
bad monitor can still create inaccurate colours. Even if you have a fantastic monitor, the other
Components can still create bad colours. So you are looking at a case-by-case kind of situation.
4. the Web browser (firefox, explorer, safari etc.)
Consider the browser to be the messenger who delivers the collared graphics to your
computer.
At the present time, most Web browsers support graphic file formats that contain essential
information about colour (such as PNG). The past standard (which is still valid for full
accessibility) is the 216 web-safe colour palette that is based on the colours that are known
to exist in the colour vocabulary of all computers (from 8 bit and up). See the 216 colour
palette below. You may also download the graphic and enlarge it to see each separate colour
square (See Figure 4.18).

figure 4.18: 216 Colour palette

4.5.2 Colours in images

The images you see on the Web are GIF, JPEG, or PNG images. In simple terms, these file formats
refer to the computer language that is at work within graphic images. It can be compared to how
some people speak Mandarin, some speak French and some speak English. Some graphic images
speak GIF, some speak JPEG, some speak PNG, some speak TIFF, etc.
These GIF, JPEG, and PNG images can be viewed by all “brands” of computers, PCs, Macintosh,
and UNIX. They also contain colour information and this information is based on RGB, on how
much (R) red (G) green and (B) blue is in the image.
Here’s some background on RGB colour theory: Computers create colours based on a special

58 LoveLy professionaL University