Photographic screen making process for SS 3

Class: SSS 3
Term: First Term
Week: 9
Age: 16-17 years
Duration: 45 minutes
Subject: Printing Craft
Curriculum Theme: Screen Printing Techniques
Previous Lesson: Plate-Making Practical and Excursion
Topic: PHOTOGRAPHIC SCREEN MAKING
Subject Matter: Photographic screen making process

Specific Objectives

By the end of the lesson, pupils/students should be able to:

Cognitive Domain

• Define photographic screen making.
• List the materials required for photographic screen making.
• Describe the steps involved in the photographic screen making process.
• Explain the purpose of each stage in the process.

Affective Domain

• Appreciate the precision and care required in photographic screen making.
• Participate actively in class discussions about the process.
• Value the importance of proper technique in achieving quality results.

Psychomotor Domain

• Outline the sequence of steps for photographic screen making.
• Identify the tools and materials used at each stage of the process.

Reference Materials

The following resources were used in planning this lesson:

• 2025 Revised 9 Years Basic Education Curriculum
• Relevant State Unified Scheme of Work
• A suitable Printing Craft textbook for SS 3
• The HeadTeacher Scheme of work

Instructional Materials

The teacher will teach this lesson with the aid of:

• A prepared screen printing frame
• Photographic emulsion
• Sensitizer
• Scoop coater
• Positive transparency (artwork)
• UV light source (exposure unit or sunlight)
• Water source (hose or spray bottle)
• Degreasing agent
• Darkroom or light-safe area
• Squeegee
• Diagrams illustrating the process

Rationale for the Lesson

This lesson is essential for students to understand a fundamental method of creating detailed stencils for screen printing. Mastering the photographic screen making process enables the production of high-quality prints with intricate designs. This knowledge is crucial for practical application in various printing industries and for entrepreneurial pursuits in graphic reproduction.

Prerequisite/Previous Knowledge

Students should have a basic understanding of screen printing, including the components of a screen printing frame and the general concept of stencil creation.

Lesson Content/Board Summary

PHOTOGRAPHIC SCREEN MAKING

Photographic Screen Making Process

Photographic screen making is a method used to create detailed stencils on a screen printing mesh by using light-sensitive emulsion and a positive transparency (artwork). The process involves several key steps:

1. Screen Preparation:

   The screen mesh must be thoroughly cleaned and degreased to ensure proper adhesion of the emulsion. Any dirt, oil, or residue can prevent the emulsion from sticking evenly, leading to pinholes or poor stencil definition.

2. Emulsion Preparation:

   Photo emulsion is a light-sensitive liquid that hardens when exposed to ultraviolet (UV) light. It is usually supplied in two parts: the emulsion base and a sensitizer. The sensitizer is mixed into the emulsion base according to the manufacturer’s instructions, typically in a dark or low-light environment, to activate its light-sensitive properties.

3. Coating the Screen:

   Using a scoop coater, the prepared emulsion is applied evenly to both sides of the screen mesh. Multiple coats may be applied to achieve a desired stencil thickness, with each coat allowed to dry partially before the next. The goal is a uniform, smooth layer of emulsion.

4. Drying the Emulsified Screen:

   The coated screen must be dried completely in a dark, dust-free environment. Exposure to any light during this stage can prematurely harden the emulsion, making it unusable. Proper drying ensures the emulsion is ready for exposure.

5. Artwork (Positive Transparency) Preparation:

   The design to be printed is prepared as a positive transparency. This means the areas that will print (ink will pass through) are opaque black, while the non-printing areas are clear. This positive acts as a mask during exposure.

6. Exposure:

   The dried, emulsified screen is placed on an exposure unit, and the positive transparency is laid directly onto the screen, usually on the side that will face the substrate during printing. A UV light source is then used to expose the screen. The light hardens the emulsion in the clear areas of the transparency, while the opaque areas block the light, leaving the emulsion soft and unhardened.

7. Wash-Out:

   After exposure, the screen is carefully washed with water. The unhardened emulsion in the areas where the light was blocked (the design areas) washes away, creating the open stencil. The hardened emulsion remains firmly attached to the mesh, forming the non-printing areas.

8. Drying and Post-Exposure (Hardening):

   Once the stencil is washed out, the screen is dried again. A final post-exposure to UV light can be done to further harden the stencil, making it more durable for printing.

9. Pinholes and Block-Out:

   The screen is inspected for any small, unwanted holes (pinholes) in the hardened emulsion. These are typically filled in using a block-out fluid or tape to prevent ink from passing through unintended areas during printing.

Teaching Methods/Instructional Techniques

Discussion, Demonstration, Guided Practice, Question and Answer, Explanation, Observation, Visual Aids.

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Explaining/Engaging

Teacher’s Activity: The teacher introduces the lesson by asking students about their previous knowledge of screen printing and how stencils are made. The teacher then explains that today’s lesson will focus on a more advanced method: photographic screen making.

Pupils’ Activity: Students respond to questions and listen attentively to the introduction.

Learning Point: Introduction to photographic screen making

Step 2: Screen Preparation

Time: 7 minutes

Teaching Skill: Explaining/Demonstrating

Teacher’s Activity: The teacher explains the importance of cleaning and degreasing the screen. If possible, the teacher demonstrates how to clean a screen and applies a degreasing agent, explaining its purpose.

Pupils’ Activity: Students observe the demonstration and ask questions about screen cleaning and degreasing.

Learning Point: Screen cleaning and degreasing

Step 3: Emulsion Preparation and Coating

Time: 8 minutes

Teaching Skill: Explaining/Demonstrating

Teacher’s Activity: The teacher explains how to mix the photo emulsion with the sensitizer in a dark environment. The teacher then demonstrates the correct technique for coating the screen evenly with a scoop coater, emphasising the need for a smooth, uniform layer.

Pupils’ Activity: Students observe the emulsion preparation and coating process, noting safety precautions and proper technique.

Learning Point: Emulsion mixing and screen coating

Step 4: Drying and Artwork Preparation

Time: 5 minutes

Teaching Skill: Explaining/Illustrating

Teacher’s Activity: The teacher explains the importance of drying the coated screen in a dark, dust-free place and the risks of premature light exposure. The teacher also explains the concept of a positive transparency (artwork) and shows examples.

Pupils’ Activity: Students listen and examine examples of positive transparencies, understanding the drying requirements.

Learning Point: Screen drying and artwork concepts

Step 5: Exposure Process

Time: 7 minutes

Teaching Skill: Explaining/Illustrating

Teacher’s Activity: The teacher explains the exposure process, detailing how the positive transparency is placed on the screen and how UV light hardens the emulsion in specific areas. The teacher may use diagrams to illustrate light penetration and blocking.

Pupils’ Activity: Students listen, ask questions about exposure times and light sources, and interpret the diagrams.

Learning Point: UV light exposure process

Step 6: Wash-Out and Post-Exposure

Time: 6 minutes

Teaching Skill: Explaining/Clarifying

Teacher’s Activity: The teacher explains the wash-out process, where unhardened emulsion is removed with water to create the stencil. The teacher also discusses the importance of drying and post-exposure for stencil durability and how to block out pinholes.

Pupils’ Activity: Students listen and clarify their understanding of stencil development and finishing.

Learning Point: Stencil wash-out and hardening

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. What is the first step in photographic screen making?
2. Why is it important to dry the emulsified screen in a dark place?
3. What is the role of the positive transparency in this process?
4. Briefly describe what happens during the wash-out stage.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Understanding photographic screen making

Step 8: Note-Taking

Time: 4 minutes

Teaching Skill: Guided Writing

Teacher’s Activity: The teacher guides pupils/students to copy the essential Board Summary notes on the photographic screen making process into their notebooks.

Pupils’ Activity: Pupils/students copy the notes carefully into their notebooks.

Learning Point: Recording lesson notes

Step 9: Conclusion

Time: 1 minute

Teaching Skill: Summarising

Teacher’s Activity: The teacher briefly summarises the main steps of photographic screen making and reiterates its importance in creating detailed prints.

Pupils’ Activity: Students listen and reflect on the lesson.

Learning Point: Consolidation of key concepts

Continuous Assessment/Further Study

Type: Homework/Practice Exercise

Instruction: Answer the following questions in your notebook:

1. List all the materials required for photographic screen making.
2. In your own words, explain why screen preparation is crucial before applying emulsion.
3. Describe the difference between the areas that harden and those that wash out during the exposure and wash-out stages.
4. Research and write a short paragraph on the different types of light sources that can be used for screen exposure.

Lesson Keywords

• Photographic Screen Making – A process using light-sensitive emulsion to create detailed stencils on a screen.
• Photo Emulsion – A light-sensitive liquid that hardens upon exposure to UV light, used to coat screen mesh.
• Sensitizer – A chemical added to photo emulsion to make it light-sensitive.
• Scoop Coater – A tool used to apply an even layer of emulsion to a screen.
• Positive Transparency – The artwork, usually black on clear film, used as a mask during screen exposure.
• UV Light – Ultraviolet light, used to harden the photo emulsion during exposure.
• Wash-Out – The process of rinsing away unhardened emulsion to create the stencil openings.
• Pinholes – Small, unwanted holes in the hardened emulsion that need to be blocked out.

Differentiation

For weaker learners: Provide simplified diagrams of each step and allow them to work in pairs to discuss and recall the sequence of the process. Focus on identifying the main stages rather than intricate details.

For faster learners: Encourage them to research the chemical composition of photo emulsion or explore different types of exposure units. Challenge them to explain the scientific principles behind the light-sensitive reaction.

Suggested Lesson Videos

For a visual demonstration of the photographic screen making process, search on YouTube for: photographic screen making process printing craft

Teacher Guide for Using This Lesson Plan

Before the lesson, ensure you have gathered all necessary instructional materials, including a screen, emulsion, sensitizer, scoop coater, and a positive transparency. Visual aids like diagrams or a short video clip demonstrating the process will greatly enhance student understanding. Begin by engaging students with their prior knowledge of screen printing to set the context. Proceed through each step of the photographic screen making process, explaining the purpose and technique involved. Encourage students to ask questions throughout the explanation. After covering all the steps, use the evaluation questions to check for understanding. Students should then be guided to copy the Board Summary notes for future reference. For practical application, if resources permit, a live demonstration or a hands-on activity in a subsequent lesson would be highly beneficial. Emphasise safety when handling chemicals and using light sources.