Oh, I agree. But I work in color every day and know it's magenta. A lot of people aren't familiar with that name and call it hot pink or similar. Just adding some cyan to it will definitely get it closer to what we typically think of when we think of purple. But, believe it or not, adding black will just make it look dirty. The only way to get to that rich deep royal purple we think of would be to add something like Reflex Blue or 072 Blue to it along with some actual red. But in all honesty, if I wanted to make purple I wouldn't even include this color. Its light value is way too high and you'd end up fighting it with darker blues to get it dark enough to be purple. Plus, every ink company I've ever worked with makes plain old Pantone Purple as a base color so that's a pretty good place to start.
