What happens when you spray with an airbrush?
We will explore the basic concepts of what happens when you spray. Once you understand why things happen, you can change or break the rules to create amazing effects.
The first step in airbrushing is learning how to hold and use the spray. Once you understand what’s happening, you can better control and modify the effects you’re trying to create.
Technical jargon warning.
An aerosol spray is a combination of two or more liquids with a gas. The liquid is broken down into tiny droplets, atomized. The atomized liquid is suspended in the gas, usually air. Liquids in suspension tend to settle over time. It gradually descends to the floor.
End of technical jargon.
When the liquid is sprayed into the air, the force of the moving air breaks it up into small droplets. These droplets will then form dots on whatever surface they land on. The height and width of these dots depends on how long it takes for the droplet to dry before hitting the surface.
- Greater air pressure = smaller dot = drier, rougher spray texture
- Lower air pressure = larger dot = wetter, smoother spray texture
Thousands of tiny dots (many of which are smaller than what you can see) form larger shapes that are determined by the user. Users try to spray with as little pressure as possible, but enough so that the paint is actually broken up.
- Thicker, chunkier paint = greater pressure to pull and atomize the paint
- Runnier, more uniform paint = less pressure to pull and atomize the paint
The pressure and size of the droplets of paint determine how much paint actually sticks to the surface.
- Greater pressure = less paint sticking to the surface
- Less pressure = more paint sticking to the surface
People are always trying to find the right balance between getting the paint coverage they want and keeping the paint from being lost to overspray.
There are a few rules you need to remember when painting. First, don’t over-spray. This can be harmful to your health over time. Make sure you wear a mask or respirator to protect yourself, and also make sure to ventilate the area well.
I’d much rather you stuck around for awhile.Airbrushes spray in a cone shape
The spray cone starts somewhere between the needle’s tip and the nozzle’s tip, depending on how much liquid you’re releasing at any one time.
- Less paint = cone’s apex closer to the needle’s tip
- More paint = cone’s apex closer to the nozzle’s tip
The size of the cone’s bottom (your spray pattern) is determined by how far you’re holding the airbrush away from the surface.
- Airbrush closer to the surface = smaller spray area
- Airbrush further from the surface = larger spray area
I should also mention that if you hold the airbrush closer to the surface, it will build up paint faster. This is because you are spraying the same amount of paint in the same amount of time over a smaller or larger area.
- Airbrush closer to the surface = quick paint build up
- Airbrush further from the surface = slow paint build up
You can see that the paint doesn’t stay on the surface for very long. It runs away and this is not good when you are painting something.
Circular Spray Pattern
Your spray pattern should be circular. You do this by holding the airbrush perpendicular to the surface, and spraying straight onto it. If you want to spray an oval-shaped spray pattern, then experiment with spraying at an angle, but usually it is best to spray straight onto the surface.
To start, you should always spray perpendicular to the surface.
Dots, dots, and more dots.
The basic shape for everything you airbrush is a circular dot. Here’s how to do it:
You have made a dot by spraying paint quickly without moving your hand. Congratulations!
- Large dots = spray further from the needle’s tip
- Small dots = spray closer to the needle’s tip
It takes more time to paint a bigger area than it does to paint a smaller area. Keep that in mind when you are painting.
- The closer you are to the surface, the greater the intensity of the spray.
- The further away you are from the surface, the less intense the spray will be.
This means that it takes a lot of time to cover large areas, but only a short amount of time to cover small areas. This means that you’ll spray details quickly, but backgrounds slowly.
Dot + Motion = Line
Start spraying a dot and move your hand in a straight line. Congratulations, you have drawn a line.
If you are a beginner, you should start by spraying paint in one spot for a longer amount of time. This will help the paint to cover more.
- If you start moving your hand before you start spraying, you will not have this problem.
- Make sure to stop moving your hand after you stop spraying. This will help to avoid creating a dot at the other end.
Good Airbrush Technique
- Air On
- Paint On
- Paint Off
- Air Off
Turn on your air before you start painting. Turn off your air after you finish painting. This is because…
- Airbrush problems usually happen when there is a big change in air pressure. This happens, for example, when you turn your air on and off. When this happens, the airbrush might spit or sputter. To avoid this, you should always turn your air on and off on a test sheet so that you don’t get paint splatters or miss fires.
- If you want to do good work, you should keep the motions for each task separate. This will help you avoid making mistakes, like putting dots at the beginning of your lines or using dagger strokes.
When you spray, move your hand parallel to the surface of the work. But what happens when you vary the distance from your hand to the work? You get a dagger stroke.
It takes practice to get good at writing in script. But it is worth it, especially if you want to learn how to write in script.
Hard Edges through Sacrifice
If you are very good at drawing and have a lot of muscle memory, you can freehand a larger shape that is two-dimensional. You will need to be very precise in your movements to keep the edges of the shape sharp.
For those of us who haven’t mastered airbrushing (or use a spray gun), we need a mask. A mask creates a barrier between the piece being sprayed and the spray. This helps to protect the piece from getting too hot.
- The closer a mask is to the surface, the more defined the edge becomes.
- The further the mask is from the surface, the less defined the edge becomes.
For example, lay a strip of masking tape onto your work and spray it. Then pull off the tape. You will get a well-defined hard line. To get a clean edge on your spray paint, take a piece of paper and hold it about an inch in front of the work. Spray it. You will get some overspray underneath your paper mask (called a stencil or shield). The edge won’t be as defined as if you taped the edge, but it should be a harder edge than what you could’ve sprayed on your own.
But there’s more! You can always learn more, but this was a general overview of the most common things airbrushers figure out on their own. Now it’s your turn- go practice! Go explore and find out what your equipment can do!
Understanding the basics of airbrushing will help you move on to more advanced ideas and concepts. Most users understand what I just told you, even if they never put it into words. Master the fundamentals and everything else becomes easier. If you don’t understand the basics, you’ll have a hard time later.