There are different types of masks you can make depending on what you are trying to accomplish. For some types a litho ortho film is helpful because you want a very steep, short scale film. For pure edge effect enhancement a fine grained general purpose film like TMAX 100 works well. You can use other general purpose films too. It just depends on the format (in my opinion). Once you're at 4x5 or larger you can use virtually any general purpose medium speed film to make an unsharp mask. However I also sometimes make special masks for 35mm, and in this case I prefer to use the finest grained film possible depending on the contrast I want. Same goes for developer. For large format Dektol is fine. For small format I am currently using dilute Perceptol (same as Microdol).