Summary:
When I use Adobe Acrobat 9 Pro to make a new resized or bookletized PDF from an existing PDF, the new PDF displays (and prints) lighter than the original.
Full detail:
I am printing music originally created in Finale 2011, professional music notation software, which has no problem displaying and printing solid black. From Finale, I print the original .MUS file to PDF by selecting 'Adobe PDF' as the printer, and when I open the PDF in Acrobat, it too, for all practical purposes, seems to display and print solid black. However, the original .MUS file contains no margins, so I then print this PDF again as a PDF within Acrobat, reducing the paper size as well as the image to fit it. In this second generation PDF, the black is noticably lighter than the original. I then print this second-generation PDF again as a third PDF on a larger paper size without stretching the image (to create margins) and this third-generation PDF is noticably lighter than the second PDF. I then print this third-generation PDF as a booklet on larger paper and again, this fourth-generation PDF is lighter than the third. Each PDF becomes lighter than its original whether I set the PDF to print in color or black and white.