UNIT 3 SCREEN PRINTING

This section explains some methods of preparing screen

                                                    Learning outcomes

By the end of the lesson, learners will be able to:

  • Understand the Photographic method of screen preparation.
  •    Design the “image/design” to be used for developing a photographic screens.
  •    Prepare or “coat” a photographic (photo-chemical) screen.

What is Photographic (photo-chemical) screen method

  • This type of screen printing method derives its name from photo which means light.
  • It is a printmaking which is done, using a screen coated with a chemical solution(photo emulsion mixed with potassium dichromate).
  • The coating solution makes it possible for the effect of light to produce an image on screen.
  • A coated screen is said to be sensitized.
  • Coating renders the screen sensitive to light penetration.
  • The design on the screen is reproduced or printed on a selected surface (substrate), by forcing ink through the screen which bears the image, with a squeegee.

Designing “image/design” used for developing photographic screens.

The inking process

  •   Set out the final image to the required size with pencil on a bond paper.
  •   Do colour separation if the colours are two or more.
  •   Trace the image if it’s one colour or images colour by colour if the image is two or more colours onto kodatrace/tracing paper with black opaque rotring/indian ink using rapidographic pen and sable brush a and allow it to dry thoroughly. This process is termed as inking.

The Computer process

  • Sketch your image/design.
  • Use your computer make the image/design.
  • Do colour separation if the colours are two or more.
  • Print out image/design.
  • Apply cooking oil/kerosene and use when dried.

Preparing or coating a photographic(photo-chemical) screen.

  • Mix 2 or 3 table spoonfuls of photo-emulsion(gelatin, seroset, alcoset, or fixoprint) with 1 table spoonful of potassium dichromate (sensitizer) into an insoluble, photosensitive(sensitive to light) substance.
  • Add a little quantity of distilled water and stir gently  and evenly, until the chemical solution is thoroughly mixed.
  • Hold the screen erect or standing in a bowl or on a insubstantial.
  • Repeat the coating two more times allowing some intervals between.
  • Allow coated screen to dry thoroughly and it is ready for exposure.
  • Use some of the coating solution/lacquer/acylic paint to seal or cover pinholes after exposure.

 

SEE ALL Add a note
YOU
Add your Comment
 

Welcome To.

KOMENCO LMS


The official komenco LMS where you learn at the comfort of your home.
Learn more

Subscribe From

top
Orbit I.T Training and Services Ltd © 2019. All rights reserved.