First of all, what is Airbrushing? How does it work?
Below you'll see the airbrush set up I have. The big block thing is the compressor, attached to it is the white hose then you'll see the gun itself. How it works is you put food colouring in the in the gun and force air through the hose and into the gun so it sprays the colour onto the cookie.
A lot of people use airbrushes because they want certain patterns like dots, lines...etc on their cookies or to give it a special touch.
The problem with airbrushes is that they can be quite costly. Think about it, a typical airbrush machine is typically in the $100+ range. You also have to buy stencils, possibly a stencil genie (that pink frame thing in the picture above), special airbrush colours.....and it all adds up.
This brings me to my next, point. While airbrushing is nice, we have so many food friendly alternatives available such as edible art paint, luster dusts, or certain techniques that can give us similar effects of airbrushing. To give you an idea of what I mean, the onesie cookie and pencil cookies below are an example of wet on wet technique where the fruit slices are painted on. The onesie cookie didn't cost me any more because I just used icing. The edible art paint may cost 8$ a tube that lasts over a year. All of which are more cost effective than buying an airbrush and it's accompanying stuff. There are a TON of options out there so to be quite honest, if you want to save yourself some money, try some of those methods instead.
If your DO want to airbrush cookies, then I highly recommend doing your research. There are a bunch of airbrushes out there. I happen to have the ADC single action airbrush and I LOOOOOOVE it. But I only settled on this one after researching the pros and cons of a bunch of them. I also found this amazing video on YouTube by Baking Sweet Hope where she does a side by side comparison and the ADC airbrush was to me the best option.
Along with your airbrush, I highly recommend purchasing a nottacookie, a stencil genie and good reliable airbrush colours.
A Nottacookie is that fake cookie looking thing on the left. It's a round thick cookie-like piece of plastic that is great for practicing. And when I say practice I don't only mean with an airbrush. You can frost it, practice writing on it, try new techniques...and guess what?! When you're done with it, just wash it off in warm water and start again! With airbrushing itself, it's really good for testing to see if your airbrush is spitting or flowing evenly, and it's great for practicing how close to get to the cookie.
The middle item is a stencil genie. They are super handy. Just pop your stencil in the middle of them (they're magnetic) and it stays in place. Now there are several ones you can buy. Sweet Sugarbelle makes one that changes sizes, some people use magnets on the back of a baking sheet, I prefer the stencil genie. It's small and easy to store.
As for the last item, those are airbrush colours. Do not try and put your regular gel food colouring you use to tint icing in your airbrush. It's only going to clog it and make it spit as well as make a big mess. Invest in some decent airbrush colours. I use these cookie countess colours but Amerimist (americolor brand) colours are also good. A really important tip I will tell you about all airbrush colours I've tried is, store the bottles upright. They leak. EVERYWHERE. Don't make the same mistake I made. That all being said, if you really are in a pinch and need airbrush colours and don't have any, thin out your gel colouring with everclear or vodka and you can use that. (then drink the rest of the bottle when you realize how much of a mess airbrushing is and have to clean it)
Now when it comes to stencils, There are 2 types, the regular plastic ones and silk screen.
The plastic stencils are overall more common and you can get from them several places like Killer Zebras, Cookie Countess among others. The problem with plastic stencils is that they need to hold together somehow and plastic isn't bendy. so if you're airbrushing a word, you'll be able to see the breaks in the words/letters as they curve like in this stencil from Cookie countess.
Another stencil option you have is silkscreen stencils. They are less