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Handmade Coater for Photo Emulsions

One method of screen printing, also called silk screening or serigraphy, involves photo-reactive emulsion. Artists often apply store-bought emulsion to synthetic fabric like polyester or screen material to perform this printing technique. Photo emulsion is expensive, however, and artists are increasingly using their own coating in place of costly photo emulsion. With this handmade coating, the photo emulsion method becomes affordable. Many artists consider this approach superior because it is the most versatile, facilitating the printing of fine line drawings, diverse lettering and photographic halftone positives.

Ingredients
- Photo emulsion is actually just white glue dyed green or blue and potassium dichromate, which acts as a sensitizer. The material is toxic and artists who make their own materials should wear gloves to protect their hands. The mixture is actually very similar to an older photographic method, which used dichromate and gum. Some people use PVA glue or mod podge rather than emulsion to make screen prints, but these prints wash out with water.
Benefits
- Artists who reap the full benefits of store-bought emulsion at a cheaper price mix PVA or Elmer's Carpenter glue with a sensitizer. Artists mix, in a light-tight space such as a darkroom, 1 tsp. ammonium dichromate with 1 ounce of water. Once this mix is dissolved, they add it to 8 ounces of glue. The resulting photo emulsion requires a 10-to-20-minute daylight exposure time to make the print. The coating rinses away with water but leaves the areas exposed to light intact.
Process
- There are diverse methods of screen printing with handmade photo emulsion, but all have three steps in common. Artists prepare the screen with a light-sensitive coating. They use a film positive cut out from a thick material, which will transfer onto the light-sensitive fabric. Finally, artists use a natural or artificial light source to expose the screen and create the print.
Precautions
- Handmade photo emulsion, like store-bought coatings, should be washed from the screen after use, unless the artist desires a perpetual exposure. Artists should store the emulsion in a cool, dark place. For thinner consistency, artists can try regular Elmer's glue in place of PVA or Elmer's Carpenter glue. Finally, artists can experiment with the ratio of synthesizer to glue, allowing them to create the photo emulsion best suited to their artistic project.

Photography