Line Thicknesses in Drawing Sheet Format

i recently created a custom, from-scratch drawing format template for a small company i work with. i created the format by starting with a blank sheet and drawing lines in the sheet format layer. when in the sheet format layer, everything looks fine, all normal looking (dark) lines.

when switching to the drawing layer the lines become dim. that's fine. but when i save the files to .pdf the lines are so dim that they are barely visible. i'm not sure how to correct this.

after some experimenting i discovered that when using "save as..." to export to .pdf these lines appear very faintly gray (see attached image). however, when going to "print" and selecting my .pdf exporter (nitro pdf creator), the lines are printed in clear dark black.

i would prefer to be able to "save as..." and export these documents to .pdf with dark lines (because i don't much care for nitro pdf and am on the verge on uninstalling it as it is). any advice on how to control the line color or possibly override them to "black & white"?

thanks!

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