In the ps2pdf(1) man page:
ps2pdf - Convert PostScript to PDF using ghostscript
ps2pdf12 - Convert PostScript to PDF 1.2 (Acrobat 3-and-later
compatible) using ghostscript
ps2pdf13 - Convert PostScript to PDF 1.3 (Acrobat 4-and-later
compatible) using ghostscript
ps2pdf14 - Convert PostScript to PDF 1.4 (Acrobat 5-and-later
compatible) using ghostscript
and
[...] they convert PostScript files to Portable Document Format
(PDF) files.
First, this isn't actually a converter since information from the input
is not preserved: ps2pdf ignores the DSC comments in the PostScript file
(contrary to viewers like gv and evince), and independently, it may
change the orientation of some pages (unless -dAutoRotatePages=/None
is used, which is not the default).
Moreover, PDF files are also accepted in input, and similarly, there
may be changes, such as:
* it may change the orientation of some pages;
* it drops the file's "screen" options (e.g. links), unless
-dPrinted=false is used (which is not the default), in which
case it drops the file's "print" options.[*]
[*] https://ghostscript.readthedocs.io/en/latest/Use.html