silk screen is a process of laying paint or through a screen that has a resist which only allows the paint through in selected areas.
multi color silkscreen printing requires a screen for each color.
the more colors the more screens that are required. the more screen the hifher the cost.
a color seperation for process printing is a method of printing four basic colours in halftone screens to produce a color print. this is a very expensive process as it requires a high degree of craftmanship to achieve a pleasing result.