Grayscale printing
 

I have a bunch of drawings that I want to send to PDF in grayscale (for patent applications).
Is there an easy way to change all the colors in a drawing to shades of gray?
I tried changing my printer settings to grayscale, but when I save as PDF, the document is still in color, I've gone through all the settings I can find in the printer setup and can't save a color PDF.
This is going to take days to go back through the drawings and change everything to shades of gray.
ANy ideas here or a secret setting or button on the OmniGraffle program to change a drawing globally??

You should be able to open the exported PDFs in Preview, then from there perform a "save as" from the file menu. In the resulting sheet that drops down, save as a PDF, and in the Quartz Filter popup menu, either select Black & White or Gray Tone, depending on your needs.

Hope that helps,

That worked perfectly thank you!