On an up-to-date TeX Live 2022, the only supported fonts for the T4 encoding are a variant of Courier that can be loaded with \renewcommant\familydefault{fcr}
, and the default Computer Modern family. All of these produce Type 3 bitmap fonts that will come out as pixelated in a PDF. Since nobody rasterizes LaTeX documents to DVI and prints them out on paper any longer, I would not recommend you use this encoding today. If you need the glyphs for one of the languages it supports, you could get better output from a Unicode font in LuaLaTeX or XeLaTeX. More to the point, your image does not appear to have been generated with \usepackage[T4]{fontenc}
.
I am not sure on what basis you believe this document used that encoding. I am unaware of any other German documents that do. If you are looking at a list of fonts and seeing their formats displayed as “Type 1” or “Type 3,” keep in mind that these are Adobe PostScript font identities, totally unrelated to the LaTeX encodings from the 1990s called T1, T2A, T3, and so on.
I also cannot reproduce your bug with the bold fonts on an up-to-date TeX Live 2022. The header displays (in an obsolete format) just fine for me with \usepackage[T4]{fontenc}
.
t4cmr.fd
does declare bold variants