Hardware Reference
In-Depth Information
Figure 12.19. Standard (4:3 or 1.33:1) versus widescreen (16:9 or 1.78:1) display aspect ratios.
Pixels
In a color monitor, each picture element (pixel) consists of three red, green, and blue (RGB)
subpixels. By varying the intensity of each of the subpixels, you can cause the overall color and
brightness of the pixel to be anything from black (all off) to white (all on) and almost any color or
level in between. The physical geometry of the RGB subpixels varies depending on the type of
display, but the shape is normally either rectangular stripes or round dots. LCD monitors normally
have the three subpixels arranged as rectangular vertical stripes in a linear repeating arrangement.
CRTs may also use linear stripes, or they can have staggered stripes or dot triads.
When you're choosing a display, the most important considerations are the combination of size and
resolution. The overall combination of size and resolution is normally expressed in pixels per inch
(ppi), but it can also be expressed in pixel pitch, which is the distance between pixels in millimeters.
A higher ppi number (or lower pixel pitch) means that fixed size images such as icons and text will
be smaller and possibly harder to read. Pixel pitch is also sometimes called
dot pitch
, in reference to
the dot-shaped subpixels used on some displays.
For a given size screen, higher resolution displays have a higher ppi number, which corresponds to a
lower pixel pitch number. As a result, the picture elements are closer together, producing a sharper
picture onscreen. Conversely, screens with a lower ppi number (which equals a larger pixel/dot
pitch) tend to produce images that are more grainy and less clear.
