If you use the LaserWriter 8.4 printer software with third-party printers (non-Apple printers), many of the enhancement options offered by these printers, such as resolution enhancement smoothing, do not work. In some cases you may not even be able to print with the existing vendor supplied PPD file.
In order to print to a non-Apple printer using the LaserWriter 8.4 driver, contact the vendor of the printer to obtain a LaserWriter 8.4 compatible PPD file.
You can also use the Generic PPD file. However, you will not have all of the printer options available to you.