Light vs. Ink
Colors created by glowing dots are not quite the same as those created by ink on the printer. Screens use the RGB system described above. Inks use the CMYK system using the colors Cyan (a kind of blue), Magenta (a kind of red), Yellow, and blacK. This is why what you see on your screen is not quite the same color when you print.
Physics Lesson:
Color from mixing pigments: Ink and paint make colors by the colors that they reflect. The other colors are absorbed, or subtracted, from the light hitting the object. The primary colors for inks and paints are traditionally said to be red, yellow, and blue. It is more accurate to say magenta, yellow, and cyan. These cannot be created by mixing other colors, but mixing them does produce all other colors.
Color from mixing lights: Lights show the colors that the light source sends out (emits). The colors from different light sources are added together to make the color that you see. A computer screen uses this process. The primary colors for lights are red, green, and blue-violet. Mixed together, they can produce all the other colors.
Color from optical mixing: The illusion of color can be created by tricking the eye. Artists of the Impressionist period created paintings using only dots of color. Newspaper photos are made of dots, also. The human eye blends the colors to "see" shapes and colors that were not actually drawn with lines, just suggested by the dots.
Screen Features
Size
Desktop screens are usually 14 - 19 in. by diagonal measurement. (This is how TV screens are measured, too.) Larger sizes are available, at a significantly higher cost. Prices are dropping, however.
Resolution
Determines how clear and detailed the image is. Pictures on a screen are made up of tiny dots. 1 dot on screen = 1 pixel (from "picture element") The more pixels per inch, the clearer and more detailed the picture.
One measure of this is the dot pitch, the distance between the dots that make up the picture on the screen. However, different manufacturers measure differently. Most measure from dot center to the center of the nearest same color dot. Some measure from the center of a dot to an imaginary vertical line through the center of the nearest dot of the same color, giving a smaller number for the same dots as the previous method. Some monitors use skinny rectangles instead of dots and so must use a different method altogether. So, dot pitch has become less useful as a measure of monitor quality. A dot pitch of .28 is very common and .26 should be good for nearly all purposes, however it is measured.
Refresh Rate
How often the picture is redrawn on the monitor. If the rate is low, the picture will appear to flicker. Flicker is not only annoying but also causes eye strain and nausea. So, a high refresh rate is desirable. 60 times per second is tolerable at low resolutions for most people. 75 times per second or more is better and is necessary for high resolutions.
Type CGA, EGA, VGA, super VGA Determines what resolutions are available and how many colors can be displayed.
New systems now come with super VGA with a picture size of 800 x 600 pixels (as a minimum) and 16 million colors |
Color
The number of colors displayed can vary from 16 to 256 to 64 thousand to 16.7 million. The more colors, the smoother graphics appear, especially photos.
The number of colors available actually depends more on the video card used and on how much memory is devoted to the display. It takes 8 bits to describe 1 pixel when using 256 colors. It takes 24 bits per pixel when using 16 million colors. So a LOT of memory is needed to get those millions of colors. Video cards now come with extra memory chips on them to help handle the load.
Reverse video |
example:
|
Cursor/ Pointer |
The
symbol showing where you are working on the screen, like:
|
Scrolling |
Moving the lines displayed on the screen up or down one line at a time |
and 
In
the olden days of just DOS, there were few choices for the cursor.
The invention of the blinking cursor was a tremendous event. Under
Windows there are a huge number of basic to fantasy cursors to
choose from.