An art diffuser allows you to blow paint from a paint bottle onto your canvas. It produces a spatter-like result. A diffuser has one small tube that is inserted into the paint bottle and a wider tube hinged to a narrower tube. The principle behind an art spray diffuser is similar to that of a straw except the wind blows in a different direction.
Pour paint into a small bottle that is shorter than the length of the narrow tube on the diffuser. Thin with suitable solvent if necessary to achieve a liquid consistency. The paint should be thin enough to be pulled up the narrow tube when you push air through the wider tube at the top.
Place the longer, narrower tube of the spray diffuser into the paint bottle.
Lift the wider tube to form a 90 degree angle with the narrow tube.
Hold the wider tube steady with one hand. With the other hand, squeeze the rubber eyedropper end to force air out of the wider tube, bringing paint up the narrow tube and on to your paper. If the diffuser you own does not have an eyedropper end, blow into the end of the wider tube that is facing you.
Repeat the previous step until you have achieved the desired look for your painting.
Practice squeezing the eyedropper end or blowing into the diffuser. Once you get a feel for how much pressure is needed to achieve a certain effect, you will be better able to handle the diffuser and create the painting style desired.
Wear protective clothing and goggles to prevent paint spatter from damaging your clothes or getting into your eyes.