Using Drawing as GreyScale Background

Hi,

I've not tried searching but no luck.

I just wish to draw over a supplied drawing, using the supplied drawing as a greyscale background. So that when printed my markups print in black against the grey drawing.

I've tried creating a viewport and setting "VP Colour" to Colour8 on all layers, but this gets messy quickly with so many reference drawings attached and does not modify dimension colours.

Is there an easy way to do this?

 

 

Thanks