At the moment I don't have any dedicated airbrush paints so I have been using what is at hand. I've got a few inks and I also have attempted to dilute watercolours to use, with varying success.
With inks, you have to be careful to make sure the pressure is low enough, no higher than around 15 PSI or you end up with a lot of spider like creatures if you are doing detail work, but if you are using thicker paints then you will need a higher pressure just to force it through.
So, I started out doing exercises of dots and dashes, lines etc but that does get boring after a while, so I was looking for something to try that would make me feel I had achieved something a bit more challenging. Enter the skull. Yup, think biker chick meets watercolorist....:)
There are loads of things you could stencil but I also wanted to practice flames. This first pic was done with watered down paints but I did have a bit of a problem with clogging. The flames were all freehand...
The next one I did with watercolour inks and no such problem, I used some curved shape stencils to add sharp edges to the flames.
It is still a work in progress, I need to add more shadow around the outer edge of the skull....Which is really the point of this post. It wasn't until I saw the photo of the work that I realised what was missing. The modern version of stepping back from your canvas, I suppose!