GAMGI uses the file extension to automatically determine the file format. To export a postscript file, just give the filename the extension .ps.

This is a rasterized color encapsulated postscript file, basically a dump of the rgb pixel information of the whole graphic area, to a big text file, that can subsequently be handled by graphic manipulation programs such as the GIMP or XV.

When using the GIMP, set the resolution to 72 dpi when loading the file, otherwise the image is rescaled, with significant loss of quality.