Making Photographic Screens from Negatives for SS 3

Class: SS 3
Term: First Term
Week: 10
Age: 16 years
Duration: 45 minutes
Subject: Printing Craft
Previous Lesson: Photographic screen making process
Topic: PHOTOGRAPHIC SCREEN MAKING
Subject Matter: Making a screen from a photographic negative

Specific Objectives

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

Cognitive Domain

• Define a photographic negative in the context of screen printing.
• List the materials required for making a screen from a photographic negative.
• Describe the step-by-step process of making a screen from a photographic negative.

Affective Domain

• Appreciate the precision and care required in screen making.
• Value the importance of safety when handling chemicals and light sources.
• Develop patience and attention to detail during the practical process.

Psychomotor Domain

• Prepare a screen frame for emulsion coating.
• Apply photographic emulsion evenly onto a screen.
• Position a photographic negative correctly on an emulsion-coated screen.
• Expose and develop a screen from a photographic negative successfully.

Reference Materials

The following resources were used in planning this lesson:

• 2025 Revised 9 Years Basic Education Curriculum
• Relevant State Unified Scheme of Work
• Printing Craft for Senior Secondary Schools, Book 3
• The HeadTeacher Scheme of work

Instructional Materials

The teacher will teach this lesson with the aid of:

• Prepared screen frame (wooden or aluminium)
• Photographic emulsion (sensitised)
• Sensitizer (e.g., potassium dichromate or diazo)
• Photographic negative (transparency film)
• Light source (e.g., UV exposure unit or strong incandescent bulb)
• Darkroom or subdued lighting area
• Squeegee or coating trough
• Washing hose or spray bottle
• Water source
• Drying rack or fan
• Gloves and safety goggles

Rationale for the Lesson

This lesson provides students with a fundamental practical skill in printing craft, enabling them to create their own printing screens. Understanding how to make a screen from a photographic negative is essential for producing high-quality, detailed prints. It builds a strong foundation for advanced screen printing techniques and applications in various industries.

Prerequisite/Previous Knowledge

Students should have basic knowledge of screen printing principles, the components of a screen printing setup, and the general concept of a photographic negative.

Lesson Content/Board Summary

PHOTOGRAPHIC SCREEN MAKING

Making a Screen from a Photographic Negative

Making a screen from a photographic negative involves several critical steps to transfer an image onto the screen mesh, creating a stencil for printing. A photographic negative, in this context, is a transparent film with the desired image or text in opaque black, blocking light from passing through.

Materials Required

1. Screen frame (with mesh stretched tightly).
2. Photographic emulsion (light-sensitive liquid).
3. Sensitizer (mixed with emulsion to make it light-sensitive).
4. Photographic negative (transparency film of the artwork).
5. Exposure unit or strong light source (e.g., UV light).
6. Darkroom or area with subdued light.
7. Squeegee or coating trough.
8. Washing facility (water hose/spray).
9. Drying rack or fan.
10. Safety gear (gloves, goggles).

Steps for Making a Screen from a Photographic Negative

1. Screen Preparation: Ensure the screen mesh is clean, degreased, and completely dry. Any dust, grease, or moisture can affect emulsion adhesion and stencil quality.
2. Emulsion Mixing: Mix the sensitizer with the photographic emulsion according to the manufacturer’s instructions. This step must be done in a darkroom or under subdued yellow light, as the emulsion becomes light-sensitive.
3. Emulsion Coating: Using a squeegee or coating trough, apply an even, thin coat of the sensitised emulsion to both sides of the screen mesh. Ensure complete coverage without streaks or bubbles. Allow the screen to dry completely in a dark, dust-free environment.
4. Negative Placement: Once the emulsion is dry, place the photographic negative (artwork side down) onto the printing side (bottom) of the screen. Secure it with clear tape to prevent movement.
5. Exposure: Position the screen and negative under a suitable light source (e.g., UV exposure unit). The light hardens the emulsion in the areas not covered by the opaque parts of the negative. The exposure time is critical and depends on the light source intensity and emulsion type. This step must be done carefully to avoid over or under-exposure.
6. Development (Washout): After exposure, immediately take the screen to a washout booth or sink. Gently spray water on both sides of the screen. The unexposed emulsion (areas covered by the opaque parts of the negative) will wash away, revealing the stencil of the image. The exposed areas remain hardened on the mesh.
7. Drying and Touch-up: Allow the developed screen to dry completely. Inspect the stencil for any pinholes or imperfections. Use block-out fluid to fill any unwanted open areas or pinholes.
8. Hardening (Optional): For increased durability, the screen can be post-exposed to UV light or treated with a screen hardener.

Teaching Methods/Instructional Techniques

Demonstration, Practical Activity, Discussion, Explanation, Guided Practice, Question and Answer

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Explaining/Recalling

Teacher’s Activity: The teacher greets the students and reviews previous knowledge about screen printing basics. The teacher then introduces the topic of making photographic screens from negatives, explaining its importance in creating detailed prints.

Pupils’ Activity: Students respond to questions about previous lessons and listen attentively to the introduction of the new topic.

Learning Point: Importance of photographic screens

Step 2: Materials Identification

Time: 7 minutes

Teaching Skill: Identification/Demonstration

Teacher’s Activity: The teacher displays and identifies all the materials required for making a screen from a photographic negative, explaining the function of each item (e.g., screen frame, emulsion, sensitizer, negative, light source).

Pupils’ Activity: Students observe the materials, listen to their functions, and ask questions for clarification.

Learning Point: Identification of screen materials

Step 3: Screen and Emulsion Preparation

Time: 8 minutes

Teaching Skill: Demonstration/Guidance

Teacher’s Activity: The teacher demonstrates how to clean and degrease the screen mesh properly. The teacher then shows how to mix the sensitizer with the emulsion in subdued light and how to apply an even coat to the screen using a squeegee or coating trough.

Pupils’ Activity: Students observe the demonstration closely, noting the techniques for cleaning and coating. They may assist in preparing the screen under supervision.

Learning Point: Screen and emulsion preparation

Step 4: Negative Placement and Exposure

Time: 7 minutes

Teaching Skill: Demonstration/Supervision

Teacher’s Activity: The teacher demonstrates how to correctly position the photographic negative on the emulsion-coated screen. The teacher then explains the exposure process, including the use of the light source and the importance of correct exposure time.

Pupils’ Activity: Students observe how to place the negative and understand the principles of light exposure for hardening the emulsion.

Learning Point: Negative placement and exposure

Step 5: Development (Washout)

Time: 6 minutes

Teaching Skill: Demonstration/Practical Application

Teacher’s Activity: The teacher demonstrates the development process by gently spraying water on the exposed screen to wash away the unexposed emulsion, revealing the stencil. The teacher emphasises careful handling to avoid damaging the stencil.

Pupils’ Activity: Students observe the washout process and the emergence of the stencil. They may practice spraying water under strict guidance.

Learning Point: Screen development and washout

Step 6: Drying and Touch-up

Time: 3 minutes

Teaching Skill: Explanation/Finishing

Teacher’s Activity: The teacher explains the importance of drying the screen thoroughly and demonstrates how to inspect for pinholes or imperfections, showing how to use block-out fluid for touch-ups.

Pupils’ Activity: Students observe the final steps and understand the need for a perfect stencil.

Learning Point: Screen drying and touch-up

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 purpose of a photographic negative in screen making?
2. List three materials needed to make a screen from a negative.
3. Describe the main steps involved in exposing a screen.
4. Why is it important to work in subdued light when handling emulsion?

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Understanding screen making process

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 making a screen from a photographic negative into their notebooks.

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

Learning Point: Recording lesson content

Step 9: Conclusion

Time: 3 minutes

Teaching Skill: Reinforcement

Teacher’s Activity: The teacher summarises the key steps involved in making a photographic screen from a negative and reiterates the importance of precision and safety. The teacher encourages students to practice the skill.

Pupils’ Activity: Students listen and ask any final questions.

Learning Point: Consolidating screen making knowledge

Continuous Assessment/Further Study

Type: Project/Practical Exercise

Instruction: In groups of three, students are to:

1. Source a simple black and white image or text design.
2. Create a photographic negative of the design.
3. Using provided materials, attempt to make a screen from their photographic negative.
4. Document each step with photographs or sketches.
5. Present their finished screen and explain the challenges faced and solutions found.

Lesson Keywords

• Photographic Negative – A transparent film with an opaque image used to block light during screen exposure.
• Emulsion – A light-sensitive liquid coating applied to the screen mesh.
• Sensitizer – A chemical added to emulsion to make it light-sensitive.
• Exposure – The process of hardening the emulsion on the screen using a light source.
• Washout – The process of rinsing away unexposed emulsion with water to create the stencil.
• Squeegee – A tool used to apply emulsion or ink.

Differentiation

For learners who struggle, the teacher can provide pre-coated screens for the exposure and washout stages, focusing only on negative placement and development. Faster learners can be challenged to research different types of emulsions and sensitizers, or experiment with varying exposure times to understand their effects on stencil quality.

Suggested Lesson Videos

For visual demonstrations, search on YouTube for: making screen from photographic negative screen printing

Teacher Guide for Using This Lesson Plan

Before the lesson, ensure all necessary materials are prepared and organised. If a darkroom is unavailable, create a temporary dark space with subdued yellow lighting for emulsion mixing and coating. Emphasise safety protocols when handling chemicals and operating light sources. Begin by engaging students with a review of basic screen printing to set the context. Demonstrate each step of the screen-making process clearly, allowing students to observe closely and ask questions. For the practical activity, supervise students closely, providing individual guidance and correcting errors immediately. Encourage students to work carefully and precisely. The Board Summary should be copied by students after the practical demonstration and evaluation, serving as a reference for their project work and future studies. Check for understanding throughout the lesson by asking targeted questions. Support weaker learners by simplifying tasks or providing more direct assistance, while challenging faster learners with additional research or experimental tasks related to exposure and emulsion types.