However, there are still problems. Before giving a presentation, make sure that your postscript slides are rendered properly with the dlb. The right border of Landscape-oriented postscript slides which have been produced with Windows applications is often not visible. Then import the modified postscript document into the dlb. Each Postscript slide is transformed to a pixmap prior to rotate it to Landscape.
Rotation is done pixel-wise.
For many other problems, it it sometimes helpful to convert a postscript file to a pdf file which is then again converted back to a postscript file. Then import your postscript slides page by page into the dlb. This reduces transmission time. If your are using a software which can produce pixmaps of your slides instead of postscript, try this option. The dlb can import most of the common image formats.