The following video tutorial is describing about how to expose the screen in screen printing. There are several ways to expose the screen. Some of them are being used as traditional method whereas others are automatic advanced method using in screen printing workshop. Screen is exposed to dry out the dampness onto screen.
When the screen is applied with emulsion or ink, it must in need to expose the screen. In advanced ways, there are screen exposing machine with timer, you can adjust the time for exposing period. This is very easy way to expose the screen in quick time. On the other hand, the screen also can be exposed through sunlight method.
In this case you have to stand in front of sunlight holding screen in your hand. But it is very difficult and tricky work to do so for several minutes in the scorching heat. So it will be better to arrange screen exposing box instead of sunlight method.
The spotlight and floodlights are also thought as source of screen exposing, the screen is kept in front of coming light but in this case you have to change the sides of screen after few minutes. Watch this video tutorial in which you are told about different method of screen exposing.