Which black ink do you need? Well it depends on what you're going to be doing with it! You would think that black is black but not exactly....If you've looked around on the website you'll see that we offer 2 "Printing Blacks", our L.P. Dense Black and our Midnite Black. And they're both great blacks for printing solids or strong rich type. But if you were to try mixing certain colors with them you would wonder "where is the blue look coming from?" Most printing blacks use a blue toner to help them achieve their rich, dense look. So if you were trying to mix a Cool Gray #3 for example; and used a dense black, your color would likely come out way too blue. That's where Neutral or mixing black comes in, it has more of a gray or washed out look to it. Great for mixing but not so much for printing a nice deep black color. That said, if you're in a pinch and need to mix a color and all you have is your Dense Black you'll probably be okay-depending on the color you're mixing. And if you need to print a dense black and only have a tube of neutral black, maybe try mixing a little reflex blue in until we can get you some more heading your way. Happy Printing!