I'm often asked what I use in my Iwata airbrush, and I have to say that after trying a number of different products, Liquitex Acrylic Ink is my preference. It's a nice consistency with a large selection of colours, plus I can mix them myself. And it's easy to clean out of my airbrush, too, which is extremely important as it isn't an inexpensive piece of equipment and I'd like to take care of it so I can use the for the rest of my life. I recently ordered a couple of opaque inks which I really like...they do need a lot of shaking as they do tend to settle between uses but they are so nice. They are permanent and non-fading. My favourites, though, tend to be the muted tones, especially muted violet and muted turquoise because I like the tones against my vibrantly coloured backgrounds. The inks are also fabulous to use to create drips and dots on the backgrounds.