Light Sources for Exposing Photo-Sensitive Films and Emulsions

All photo materials are sensitive to ultraviolet (UV) light. The black parts of your film positive protect those parts of the stencil that you want to print from being affected by the UV light.

After exposing your film or emulsion to the light, in contact with your film positive, these protected areas are washed out, leaving the hardened, non-image area of the stencil to seal the screen fabric and allow ink to pass through only the washed out areas.

Types of exposures:

Sunlight No cost, but unpredictable.

Photoflood bulb Or 150 watt, 250 watt bulb. The higher the wattage, the shorter the exposure time. Inexpensive, good for bold designs, fairly dependable, but bulbs may be changed often.

Blacklight Moderately expensive, very dependable, excellent results with fine detail, short exposure time.

Self Standing Quartz Halogen Exposing Unit Very expensive; the best you can buy for professional, continual use.