Quote Originally Posted by Oren Grad View Post
Here's a link to a document from Harman on contrast control with Ilford Multigrade papers. It includes a table ("Dual colour filter settings", p. 3) of combined Y/M filtrations to achieve similar exposures across the grades:

http://www.ilfordphoto.com/Webfiles/...8932591755.pdf

The same information is included on the insert provided with each box of Ilford paper.
These recommendations work, but it is important to understand what they actually do.

Their goal is to give you the same print density with each contrast setting, but they only apply to a single reference tone - most likely a middle grey.

So if it is not that reference tone that you are seeking to match across the contrast grades, you may not get exactly the result you want.

Some people prefer to match highlight tones instead, so they do their own calibration to achieve their own goals.

The published suggestions will get you closer than nothing though.