What causes line art to go photo-negative in PDFs from Word?

[teamtrainers]

What would cause line art to appear as a negative in a PDF file printed from
Word? I have a large file with clip art and a diagram imported from
PowerPoint. The art was recolored to grayscale. The first time I used "Save
as PDF," they came out fine. I made no (intentional) changes to the settings
or my computer other than a few Windows Updates (no Office Updates). A week
later I made text-only changes to the file. When I created the PDF, many of
the clips looked like photo negatives--white on black. As a test, I re-PDFed
the old file and tried a new file with a freshly downloaded clip, and both
exhibit the same problem. I found a workaround, which was to return them to
color (including the diagram that was not color before). But that will not
work long term. I am running a Dell with Office 2007 SP2 and Vista SP2, and I
found nothing on this issue here or in the MS Knowledge Base.

 

[DeanH]

I tend not to use the Word Image Control - including Grayscale - because I
have found this causes more problems in the long run.
I do all the changes in the application where the image is, save as JPG (for
example) and insert this file into Word. Then (cross-fingers) any convertion
works well.
Hope this helps
DeanH

 

[teamtrainers]

While I agree with you, Dean, in this case I can't: the graphics in question
are all clip art either from Microsoft or a CD. Turning them back to color
fixed most of the problems. For the PowerPoint, I had to OLE link instead of
inserting it as a graphic. Thanks, though. If anyone runs into this and finds
a fix, please comment.