Perple_X plotting programs generate Encapsulated PostScript that can be viewed and edited in most commercial 
graphics programs. However for fast viewing and/or conversion I strongly recommend GSview: 

GSview (aka Ghostview) is an efficient, free, PostSctipt viewing program, it can also be used to read and generate 
a variety of different file types (e.g., *.png, *.pdf, *.jpg). Postscript interpreters slightly misalign phase 
field fills, which creates an odd pattern in postscript view, converting to pdf format eliminates this pattern and 
substantially reduces file size, making subsequent editing easier.

COPYING AND INSTALLATION:

GSview is actually an interface to a PostScript interpreter called Ghostscript which must be installed first. 

Copy both Ghostscript and GSview by following the links given at 

https://pages.cs.wisc.edu/~ghost/

GSview is an updated version of the original Ghostview interface. I am fairly sure Ghostview is no longer maintained
and is largely obsolete. However, if you find a working copy it is adequate.

Functional copies of Ghostscript and GSview for WINDOWS can also be copied from:

https://www.perplex.ethz.ch/perplex/ibm_and_mac_archives/WINDOWS/ghostview/