When creating a pdf from AutoCAD, the program works smoothly and efficiently and gives an excellent preview in Acrobat.  However when printing, any area with text masks (sometimes called wipeouts) in the drawing will print out as solid black.  These are actually small images under the text to make it readable by hiding the linework behind the text.  I recall that older printers had a problem with this - but I don't know about a fix.  Any ideas?