I have used black and white intensifier from Photographer's Formulary, and I like it for adding density across the board. I also like to use a strong dilution of selenium toner as an alternative to about +1 of development. (I got this method from reading "The Negative".) I like this because it increases contrast more than the intensifier, not just overall density. If using small format film and I want to develop N+2, I will usually develop N+1, or slightly more, and tone with selenium instead of doing the full N+2.
I am wondering if these two methods can be used in tandem, or if there is perhaps some chemical change that occurs on the emulsion after one of them that will prevent the other from being effective.
If it will work, which would have to come first?
Thanks in advance.