Why isn’t my image perfect?
Perfection in monitors is a relative term. Monitors are designed to provide a balance between cost and performance. Every monitor that leaves the assembly line is "perfect" based on the standards and tests that are performed on it during the manufacturing process. That perfection may be marred during transportation, handling and setup of the unit.

In addition, many external factors can affect the monitor image including, but not limited to, the video controller, electromagnetic fields in the work environment and the earth’s magnetic field. Over time wear and tear on the monitor will also take its toll on the image.

Each monitor model is subject to a certain set of standards that includes measurements of screen geometry. These measurements are actually a range of numbers that vary by as much as ±30% depending on the measurement and where it is taken.

Please remember that these measurements must be taken on the CRT itself and not relative to external factors such as the monitor bezel, and that they must be taken on a monitor that has been adjusted to the best image possible.

In addition, you will see different "imperfections" at different resolutions. Changing resolution will help determine if there is a problem with the monitor or if the problem is caused by one of the other links in the image chain.

The following provides answers to many commonly asked screen geometry questions and provide basic troubleshooting steps to determine if the monitor is within factory specifications.

Early in monitor history the ability to expand the image "edge-to-edge" indicated a high performance monitor. As monitor technology advanced this ability became easier to achieve and today most monitors are capable of "edge-to-edge" or nearly "edge-to-edge" images.

While in the past expanding a monitor’s image "edge-to-edge" provided for larger features in the display, this is not always desirable in today’s Graphic User Interface environment when window control buttons are often located very close to the edge of the image. Increasing image size "edge-to-edge" could actually cause some control buttons to be hidden behind the bezel.

It is still important to utilize as much of the monitor’s display area as possible. Achieving maximum usage is a combination of the monitor’s and video controller’s capabilities. An "edge-to-edge" display is not necessarily desirable or achievable (especially with Macintosh timings) in every resolution.

The term "edge-to-edge" is defined relative to the edge of the bezel. Many monitor manufacturers are maximizing the size of the bezel opening allowing users to take advantage of technological advances in monitor design which allows the image to be expanded to utilize a larger portion of the raster. A larger opening means a larger image size, but it may also mean that the monitor is not "edge-to-edge". In this instance being "edge-to-edge" is not important since the user gets the maximum image size possible.

Some monitors that are "edge-to-edge" actually have a smaller maximum image size that those that are not since the bezel of the "edge-to-edge" model actually covers usable image area.

The edges of my display are not straight. Is this the fault of my video card?
Not necessarily. Please be make sure that the video card has been set up properly, including the vertical refresh rate. If the problem persists, it may be due to normal manufacturing variances in the monitor. While edges of the image may not be straight when viewed relative to the edge of the bezel (the cutout in the front of the monitor), this does not necessarily indicate a problem as long as the image closer to the center of the monitor are straight.

Why is one edge of the image lower than the other edge?
The earth's magnetic field may be interfering with the magnetic field generated by the monitor causing a slight rotation of the image. To have the best alignment, orient the monitor so that when sitting in front of the monitor, you are facing a westerly direction and the monitor is facing east. As a guideline, there may be approximately up to an 1/8" rotation allowed when viewing a solid background image at full screen size.

Some models have a Tilt/Rotation control that allows the user to compensate for minor variances.

Why do the characters in the corner of the screen look fuzzy?
Because CRTs are not perfectly spherical and the electron gun is not located at the end of the ovaloid described by the surface of the CRT the focus on the screen will not be uniform. Circuitry in the monitor or the design of the CRT compensates for some of this variance. The monitor is adjusted so that the focus is best in an area around the center.

When I have a white background up, such as in a word processor, some areas of the screen are a little darker than the center. Is my monitor bad?
The monitor is not bad. The electron beams pass through either a shadow mask or aperture grille which aims them at the proper phosphor color. In high resolution displays, these beams are focused to a fine point, and are slightly smaller than the opening through which they must pass. Nearer to the edges of the tube, the beams may not pass through the exact center of the opening, and part of the beam is blocked. This is called eclipsing. The result is that less beam area strikes the phosphor, and the illumination there is less than that at or near the center of the CRT. This is not an uncommon situation, and the term used is brightness uniformity. Up to 30 percent less illumination than the central area is considered acceptable. Brightness uniformity should not be confused with purity, as discussed earlier.

The picture on my display curves in near the bottom on one side. I have tried the Pincushion and Trapezoid controls, but I can’t get that curve out. What can I do?
The component that sweeps the electron beam across the face of the CRT is called the yoke. It resides on the neck of the CRT and has magnetic windings for vertical and horizontal deflection. The electron beams cannot be made to give absolutely perfect geometry at the edges.

In addition different resolutions cause different geometric behavior. To compensate for these variations, the monitor includes circuits and controls to adjust the sides of the display. To keep costs reasonable, these functions are somewhat coarse. To add more functions and finer control, the monitor circuits need to be much more complex, and therefore add to its cost. The area of the display inward of the edges is not subject to these distortions, and it is recommended that the user adjust the geometry controls for the best overall effect.

The color on my monitor is washed out. What can I do?
First properly adjust the brightness and contrast. If you still feel that the colors are washed out then if your model has color control select one of the other temperature settings or adjust the RGB color balance.

Unlike televisions, monitors do not have a color level control to control overall color. Once the monitor is properly adjusted reducing the brightness will also saturate colors, but reduce overall picture intensity slightly.