Lights For Screen Printing Exposure
Exposure lights are one of the key tools for screen printing, without them you cannot expose your screens and all your efforts would be in vein. However, with the right lights, you can expose your screens, as an alternative you can expose your screens under natural sunlight.
You can either purchase a UV exposure kit/unit which can be quite expensive or you can buy a cheap 1000wat halogen light on eBay and build your own which I have pictures of below. You must be very careful with self-built exposure lights as there is always a fire risk when using these, please don’t leave them unattended.
The units I have built with 1000wat halogen flood lights have been made with the light at about 15 inches away from the screen. A safe bet for exposure time of your screens is around about 4 minutes, this can vary dependent on your setup so you will need to experiment. Please refer to the table below which has a rough idea of different heights and lights.
Two other key points when exposing your screens before printing:
- Place a blacked-out material that sits under the screen and fits the inner edges of the screen frame and pushed very tightly on the underside of the screen mesh.
- Place a sheet of glass on top of the screen roughly the same size as the outer edge of the screen frame where you put your film positive to create a seal.
An example of this is a sheet of wood with black foam stuck to it, bare in mind the heat produced from the light may warp the foam. This is to make sure the artwork does not move when you expose your screen, otherwise, this may cause ghosting. This will be covered in more detail in the steps below.