Poor quality drawings in issued patent (and on PAIR)

[MR]

It appears that the USPTO server converts drawings to 300 DPI pure black and white (i.e., not grayscale) and that it is the converted drawings that appear on PAIR and in the published patent. As a result, fine lines (e.g., lines that are visible at 600 DPI) may become broken (and appear dashed) or disappear entirely.  Is there a way to control or at least anticipate how drawings will appear after conversion?  The software we use to print to a PDF that the USPTO will accept (e.g., bullzip, cute PDF, or Nuance) exacerbates the uncertainty because their output is grayscale. 

[memekit]

I crisped up my graphics by using a "draw bitmap" function on inkscape.  Also try just image enhancement on power point.  Then print to PDF Pro (don't just 'save as pdf' actually print as pdf) and adjust the dpi and you can see and pre-tweak the outcome.

[MR]

Did you buy PDF Pro from pdfpro10.com?  I don't have a copy.

[memekit]

Yes, this is the program I use for all my USPTO .pdf uploads.  Search for reviews there may be even better.

[smgsmc]

It appears that the USPTO server converts drawings to 300 DPI pure black and white (i.e., not grayscale) and that it is the converted drawings that appear on PAIR and in the published patent. As a result, fine lines (e.g., lines that are visible at 600 DPI) may become broken (and appear dashed) or disappear entirely.  Is there a way to control or at least anticipate how drawings will appear after conversion?  The software we use to print to a PDF that the USPTO will accept (e.g., bullzip, cute PDF, or Nuance) exacerbates the uncertainty because their output is grayscale.

I use Nitro.  It lets me set the output parameters.  I output to 300 dpi black and white.  I make sure the features on the originals are coarse enough (no thin lines, no small dots, ...) and drawn in black and white mode so that they reproduce properly at these settings.  I thought most pdf print software let you set the output quality.

[MR]

When you zoom all the way in on a PDF generated with Nitro (i.e., to 6400% in Acrobat), do you see black and white squares or various shades of gray?  All of the PDF printers I have (e.g., Nuance, Bullzip, CutePDF, Acrobat Pro) generate grayscale output only, as far as I can tell; there's no option to generate pure black and white output.

[dbmax]

Some drawing programs (eg DesignCad) have a minimum-pen-width setting in the print dialog which prevents the problem discussed in the OP, whether printing to paper or to pdf files. I keep mine set to 0.13mm.

[smgsmc]

When you zoom all the way in on a PDF generated with Nitro (i.e., to 6400% in Acrobat), do you see black and white squares or various shades of gray?  All of the PDF printers I have (e.g., Nuance, Bullzip, CutePDF, Acrobat Pro) generate grayscale output only, as far as I can tell; there's no option to generate pure black and white output.

Oh, sorry.  I can set the output dpi in Nitro.  I do my own drawings and make sure not to select any greyscale or color features (black and white only) within the drawing programs; and (as dbmax posted) select linewidths wide enough to avoid any drawing elements from unexpectedly morphing or vanishing.

[JV]

I used to have this problem.  It turned out that, while I though all of my lines were black (they sure looked black!) they were actually not true black.  This caused the black-and-white-boxes-effect when I zoomed in on lines after conversion by the USPTO.  Once I adjusted my line color to true black, the problem went away.
Note: I'm probably a bit different than most, I do all of my own patent drawings using CAD (PTC Creo) software.