For example, if you want to manually align a text object to a graphic object and will be printing to a LaserWriter, you need to make the alignment at 400%. The resolution at that zoom view is 288 dots per inch (dpi) which is the closest to the LaserWriter's resolution of 300 dpi.
Sometimes objects aligned at 3200% look fine, at 400% look bad and at 100% look good again. A 0.1 point line created with the zoom level at 800% with be one pixel wide on the screen. The same line displayed at 100% will still be one pixel wide.
Because the zoom levels are multiples of 72 dpi its easy to convert from percentage zoom to dpi. Conversion of percentage zoom to dpi:
100% - 72 dpi
200% - 144 dpi
400% - 288 dpi
800% - 576 dpi
1600% - 1152 dpi
3200% - 2304 dpi
Additionally, the capacity to zoom is based on the size of the document. A one page document can be zoomed to 3200%. At the largest size, 100 x 100 inches, the user can only zoom to 400%. This is due to a limitation within the QuickDraw coordinate system.