Hi Jo… I am self taught, and don’t have the luxury of a Dinky Doodle… I am running on a $20 ebay special.
I know there are specialist airbrush colours that are available, which probably do work best.
As a self-confessed “Queen of budget”… I use what i have.
I have found that the main thing is, your colour has to be pretty thin, otherwise your airbrush will clog and spatter.
Normal liquid food colours can be thinned with alcohol. I use vodka. The benefit of this is, alcohol will speed up drying time between layers as well.
I am a recent convert to Progel colours as well. Although they are a gel, they do thin with alcohol & have an amazing colour range.
I have a few tips put together on my facebook page. I will try to insert a link for you.
https://www.facebook.com/#!/photo.php?fbid=529551687125014&set=pb.450634018350115.-2207520000.1389178924.&type=3&theater
P.S. Ensure you clean properly after each use, to ensure no residue build-up inside the airbrush.
Hope this helps
Julez
Julez, https://www.facebook.com/pages/Allways-Cakes/450634018350115?ref=hl