When it comes to creating color schemes, most of us start with 'oh, these are my favorite colors so I'll use them'. And while that might seem perfectly reasonable, what about if we try to print them, and we find that we can't? Just because we can see color doesn't mean we can get a print that looks exactly the same. Is it something wrong with the printer? No – it's something far more fundamental. And if we understand what it is, and how it works, we can make better, more informed choices. And that's just one of the things we need to consider.
You should have a computer.