Gray lines while converting 2010 Word images to pdf

Question

With the new Acrobat version X1, I've run into a problem every time I try to convert images on a Word 2010 document to a PDF.  While all lines on the document are black, many of the lines including bubble-notes appear very light grey, and difficult to read.  I've searched for months for a solution without any luck, and I tried other computers with different versions to verify it wasn't just my machine. 
Is there a specific setting that I need to change during conversion so that black lines remain black instead of this weird gray-scale problem?  See below for example.
Before, snapshot taken from Microsoft Word:
After conversion in .PDF document format, taken from Acrobat XI:

Answer 1

Word:
I attempted to change the picture format, specifically the image control.  Three of the four options - Automatic, Grayscale, Black & White - produced no different results.  The fourth "Washout" option made the problem worse, as the dwg became brighter in both the .doc and the .pdf.
Autocad:
Changing the lineweights made no difference either.  Our company standard is black background, white object lines, but even when I reverse it and make the line colors as dark as possible, I get grey lines during conversion.