Apple AppleVision monitors (OS 7.1) - Manual (Page 50)

3 Adjust the convergence at the center of the screen by moving the handles on the
grid lines.
If your AppleVision monitor supports it, there are additional handles near the
top and bottom of the monitor. Adjust the top convergence first, then the
bottom. You may need to readjust the center convergence after moving the top
or bottom.
Click the Reset button to undo all your changes. This is a quick way to start
over if you’re dissatisfied with your results so far.
Move the Convergence Control window to different areas of the screen, then
look at the text and picture in the window to judge the results of your
adjustments.
4 Click OK to keep your settings, otherwise click Cancel.
When you adjust convergence, it’s best to use the center of the screen image
as a reference point, rather than the outside edges. You may have to
compromise between good convergence at the center of the screen image and
good convergence at the edges.
50 Chapter 6