I compile the same tex using two commands:
latexmk --pvc --pdfps ./main.tex
and
latexmk --pvc --pdf ./main.tex
Then view both pdf files using evince, at the same scale (170%).
The result using --pdfps (on the left) has heavier font that the result using --pdf (on the right):
Do you know why?
Update:
Here comes a minimal example:
$ cat main.tex
\documentclass{article}
\usepackage{amsthm}
\usepackage{amsfonts}
\usepackage{amsmath}
\usepackage{amssymb}
\title{Compare}
\begin{document}
\maketitle
$$
a_\textit{ivanov} \wedge b_\mathit{sidorov} \rightarrow \text{petrov}^{2^{x}}
$$
\end{document}
Running pdffonts gives:
$ pdffonts ./pdf.pdf
name type encoding emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
JADGUW+CMR17 Type 1 Builtin yes yes no 4 0
GFYLUX+CMR12 Type 1 Builtin yes yes no 5 0
IEHANU+CMMI10 Type 1 Builtin yes yes no 6 0
WLJBIP+CMTI7 Type 1 Builtin yes yes no 7 0
GHNOGE+CMSY10 Type 1 Builtin yes yes no 8 0
UWWUVN+CMR10 Type 1 Builtin yes yes no 9 0
RKDUWA+CMR7 Type 1 Builtin yes yes no 10 0
EUVFVQ+CMMI5 Type 1 Builtin yes yes no 11 0
$ pdffonts ./ps.pdf
name type encoding emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
RRWQTJ+CMMI5 Type 1C WinAnsi yes yes no 22 0
EBFDMR+CMR7 Type 1C WinAnsi yes yes no 20 0
AFJYHC+CMR10 Type 1C WinAnsi yes yes no 18 0
ILWBCN+CMSY10 Type 1C Custom yes yes no 16 0
OFQOVE+CMTI7 Type 1C WinAnsi yes yes no 14 0
IEOASN+CMMI10 Type 1C WinAnsi yes yes no 12 0
LWIAFV+CMR12 Type 1C WinAnsi yes yes no 10 0
ZGILVG+CMR17 Type 1C WinAnsi yes yes no 8 0
The --pdfps version uses Type 1C fonts, which may be the reason...
pdffontsutility report? – David Carlisle Sep 10 '18 at 15:39