Let's construct mwe.tex containing
\documentclass{article}
\usepackage{pstricks}
\begin{document}
test
\end{document}
and run
latex mwe && dvipdf mwe
or
latex mwe && dvips mwe && ps2pdf mwe.ps
This prints
%%%% WARNING: Transparency operations ignored - need to use -dALLOWPSTRANSPARENCY
on a tty. Of course, one can do as the message says and add the corresponding command-line option. Still, I feel that the transparency stuff shouldn't even be in the Postscript file unless it is really used. So could pstricks be a bit more economical and not issue the transparency-related commands by default (or, equivalently, issue them only if opacity and the like is really used in the user's LaTeX input)? Alternatively or in addition, could ghostscript be a little less fussy about transparency and make ALLOWPSTRANSPARENCY default?
Thank you in advance,
Peter