This texture type is called acoustic, popcorn, or cottage cheese. It is usually achieved by mixing an aggregate (small chunks of material such as vermiculite or polystyrene) with ceiling paint and then spraying the mixture using a special texturing spray gun. Acoustic texture is a finished surface after spraying, but can also be painted to a color of choice. Most new home ceilings are sprayed with this type of texture in medium aggregate.
Acoustic texture can come in a variety of styles:
Splatter, orange peel and knockdown textures are all related textures.
Splatter is a texture of it's own, as well as a starting point for other textures.
Orange peel is actually a tiny splatter and has become very common. It
can be sprayed on both walls and ceilings, as well as painted however
you like. It can be varied in it's application from fine to
course. A medium application is shown below.
Knockdown is created by applying a splatter and then using a flat knife to "knock down" the points. Knockdown texture makes a nice modern ceiling or wall finish. It can be varied from a small, fine pattern to a larger, dragged-together look called "Spanish Lace" or "Mediterranean". A well done knockdown texture can increase your home's value.
These picture show before and after knocking down the splatter. Both pictures are before the textures have been painted.
There are a number of techniques that will produce a variety of beautiful looks.