I'm trying to print a pdf that I cannot manipulate. It has some color on the document, but the majority of the pages are black text. When I print it, there is a dark halo around the letters in the text. I've tried printing it as a pdf and taking into photoshop and printing from there, but they look the same. I've turned over black overprinting, no help. But, when I open it in photoshop and convert it to grayscale, the halo is gone. Help!
One strong possibility is that what you think is black text really isn't pure black, i.e., it isn't grayscale or CMYK=(0,0,0,K) but rather some rich black CMYK mixture or RGB. The halo that you are seeing might be due to the slightest misregistration of the colors.
If the problem is RGB black text and if the text is R=G=B such as you might get out of Microsoft Office applications, there is an option for PostScript printing from Adobe Reader and Adobe Acrobat for Treat grays and K-only grays in the Color Management Advanced options. That forces any R=G=B to be CMYK=(0,0,0,K).