Emulsion in printing refers to a light-sensitive colloidal mixture used in the preparation of photographic plates, film, and printing screens. This mixture typically consists of silver halide crystals suspended in a gelatin solution, which reacts to light exposure to create an image. In screen printing, emulsion is used to coat the screen, hardening when exposed to light to form a stencil for ink application.


Light-sensitive Coating


  1. Screen Printing: In screen printing, a photosensitive emulsion is applied to the screen mesh. After exposure to UV light through a positive image, the emulsion hardens and blocks ink from passing through, creating a stencil of the design.
  2. Photographic Film: Traditional photographic films are coated with an emulsion containing silver halide crystals, which react to light exposure to capture images.
  3. Offset Printing Plates: Emulsion is applied to offset printing plates. When exposed to light, the emulsion forms a detailed image that transfers ink onto the printing surface.


  1. Proper Coating: When applying emulsion to a screen, ensure an even coat for consistent results. Use a scoop coater to achieve a uniform layer.
  2. Controlled Environment: Apply and store emulsion in a dark, temperature-controlled environment to prevent premature exposure and degradation.
  3. Accurate Exposure: Use a light exposure unit with a timer to ensure precise exposure times. Underexposure or overexposure can lead to incomplete stencils or loss of detail.
  4. Regular Testing: Test the emulsion periodically for sensitivity and quality. Changes in formulation or storage conditions can affect its performance.
  5. Clean Equipment: Clean screens and coating tools thoroughly before applying emulsion to prevent contamination and ensure the best results.

By understanding the role of emulsion in printing and following t