Hi Nico,
I think, nowadays, its relatively easy to get 300 dpi. 600 dpi
will quickly replace that. I never need to turn on 1200 dpi to
get a quality drawing -- even on A size paper.
Inkjet printers are probably *not* a good idea for schematics
as they tend to have larger dot sizes. IMO, inkjet only makes
sense for really low power and/or "color" (neither of which
seem to be necessary -- IMO -- for producing schematics).
I think pen plotters were in the 0.3mm region for line widths
(rapidograph tip). If so, figure ~100 per inch (ignoring ink
bleed). So, every three inches of plotter dimension corresponds
to an inch of 300dpi printer dimension. I.e., an A size sheet
has (roughly?) the same amount of "detail" as a C size sheet on
the plotter. B size print would equate to a D size plot?
I'll have to drag out a plotter and see.
(or, has my mental arithmetic slipped a gear somewhere along
this process?)