Steps in plate making, correcting on plate and plate preservation for SS 3

Class: SS 3
Term: First Term
Week: 7
Age: 16 years
Duration: 45 minutes
Subject: Printing Craft
Previous Lesson: Safety Precautions in Plate Making
Topic: PLATE MAKING
Subject Matter: Steps in plate making, correcting on plate and plate preservation

Specific Objectives

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

Cognitive Domain

• Identify the sequential steps involved in plate making.
• List different methods for correcting errors on a printing plate.
• Explain the importance of preserving printing plates.

Affective Domain

• Appreciate the need for accuracy and attention to detail in plate making and correction.
• Value the proper preservation of printing plates for future use.
• Adhere to safety rules during plate making and handling.

Psychomotor Domain

• Demonstrate the exposure process of a printing plate.
• Apply at least one method to correct an error on a plate.
• Show how to properly preserve a printing plate.

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 Textbook
• The HeadTeacher Scheme of work

Instructional Materials

The teacher will teach this lesson with the aid of:

• Pre-sensitized printing plate
• Artwork film (positive/negative)
• Exposure unit/light source
• Plate developer
• Cotton wool or sponge
• Plate gum
• Plate correction fluid
• Scraper
• Water
• Storage rack or cabinet

Rationale for the Lesson

This lesson is essential for students to understand the practical processes involved in preparing printing plates, which is a fundamental stage in offset lithography. Mastering plate correction and preservation techniques ensures print quality, reduces waste, and extends the lifespan of valuable printing materials. This knowledge directly supports the production of high-quality printed materials.

Prerequisite/Previous Knowledge

Students should have basic knowledge of printing processes, the different types of printing plates, and the importance of pre-press operations.

Lesson Content/Board Summary

PLATE MAKING

Steps in Plate Making

Plate making involves several critical steps to transfer the image from the artwork onto the printing plate. The common steps include:

1. Artwork Preparation: Ensuring the artwork is clean, correctly sized, and ready for film output or direct computer-to-plate (CTP) transfer.
2. Film Output (for conventional plates): Creating a photographic film negative or positive of the artwork.
3. Plate Exposure: Placing the film (or using a CTP system) over a pre-sensitized plate and exposing it to UV light. The light hardens the image areas on the plate.
4. Plate Developing: Applying a developer solution to the exposed plate. This washes away the unhardened, non-image areas, leaving the image areas on the plate.
5. Plate Rinsing: Washing the plate with water to remove excess developer and stop the developing action.
6. Plate Gumming: Applying a thin layer of plate gum to protect the non-image areas from oxidation and make them hydrophilic (water-attracting).
7. Drying: Drying the plate before storage or mounting on the printing press.

Correcting on Plate

Errors can sometimes occur on a printing plate, requiring correction before printing. Common methods for correcting on-plate include:

1. Using Plate Correction Fluid (Deleter): For removing unwanted image areas. The fluid chemically dissolves the image part, making it non-printing. It is applied carefully with a cotton swab.
2. Scraping: For small, isolated specks or unwanted dots. A sharp, non-abrasive scraper can be used gently to remove the unwanted image area without damaging the plate surface.
3. Adding Image (Re-sensitizing/Re-exposing): For adding missing small details or text. This involves re-sensitizing a small area, exposing it to light with the correct film, and then re-developing. This is a more complex process and is often done by skilled technicians.
4. Blocking Out: Using opaque tape or a special opaque pen on the film before exposure to prevent certain areas from printing. This is a pre-exposure correction but can be considered if the plate has not yet been exposed.

Plate Preservation

Proper preservation of printing plates is essential to maintain their quality and extend their usability for future print runs. Key preservation techniques include:

1. Thorough Cleaning: After each print run, plates must be thoroughly cleaned to remove all ink and gum residues. Use appropriate plate cleaners and water.
2. Gumming: Re-gumming the plate with a fresh layer of plate gum after cleaning. The gum protects the non-image areas from oxidation and keeps them hydrophilic.
3. Drying: Ensuring the plate is completely dry before storage to prevent water spots or mildew.
4. Proper Storage: Store plates flat in a dedicated plate rack or cabinet. They should be protected from light, dust, moisture, and physical damage (scratches, bends).
5. Temperature and Humidity Control: Store plates in a cool, dry environment with stable temperature and humidity to prevent degradation of the plate coating.
6. Interleaving: For long-term storage, placing acid-free paper or thin plastic sheets between plates can prevent them from sticking together or scratching.

Teaching Methods/Instructional Techniques

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

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Explaining/Questioning

Teacher’s Activity: The teacher greets the students and reviews the previous lesson briefly. The teacher then introduces the topic “Plate Making” by asking students what they think happens after artwork is prepared for printing. The teacher explains that today’s lesson will cover the steps involved in making a printing plate, how to correct errors on it, and how to preserve it.

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

Learning Point: Plate making importance

Step 2: Steps in Plate Making

Time: 8 minutes

Teaching Skill: Explanation/Listing

Teacher’s Activity: The teacher explains the sequential steps involved in making a printing plate, from artwork preparation to gumming and drying, using clear language and visual aids if available. The teacher lists these steps on the board.

Pupils’ Activity: Students listen, ask questions for clarification, and copy the steps into their notebooks.

Learning Point: Plate making sequence

Step 3: Demonstration of Plate Making

Time: 8 minutes

Teaching Skill: Demonstration/Guidance

Teacher’s Activity: The teacher demonstrates the practical steps of plate exposure, developing, rinsing, and gumming using the instructional materials. The teacher guides students to observe safety rules during the demonstration.

Pupils’ Activity: Students closely observe the demonstration, follow safety instructions, and ask questions about the process.

Learning Point: Practical plate exposure

Step 4: Correcting on Plate

Time: 7 minutes

Teaching Skill: Explanation/Discussion

Teacher’s Activity: The teacher explains the common types of errors that can occur on a plate and introduces various methods for correcting them, such as using correction fluid and scraping. The teacher discusses when each method is appropriate.

Pupils’ Activity: Students listen, participate in the discussion, and note down the correction methods.

Learning Point: Plate correction methods

Step 5: Demonstration of Corrections

Time: 7 minutes

Teaching Skill: Demonstration/Practical Application

Teacher’s Activity: The teacher demonstrates how to correct a simulated error on a plate using plate correction fluid and a scraper. The teacher emphasizes precision and care to avoid damaging the plate.

Pupils’ Activity: Students observe the demonstration and identify the tools and techniques used for corrections.

Learning Point: Error correction application

Step 6: Plate Preservation

Time: 6 minutes

Teaching Skill: Explaining/Listing

Teacher’s Activity: The teacher explains the importance of plate preservation and describes the methods for proper cleaning, gumming, drying, and storage of printing plates to ensure their longevity and reusability. The teacher lists these methods on the board.

Pupils’ Activity: Students listen, ask questions, and note down the plate preservation techniques.

Learning Point: Plate preservation techniques

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. List three steps in plate making.
2. Mention two methods for correcting errors on a printing plate.
3. Why is it important to preserve printing plates?
4. Describe one way to preserve a printing plate.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Plate making knowledge

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 steps in plate making, correcting on plate, and plate preservation into their notebooks.

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

Learning Point: Key lesson points

Step 9: Conclusion

Time: 3 minutes

Teaching Skill: Summarizing

Teacher’s Activity: The teacher briefly summarizes the key points of the lesson, reiterating the importance of accurate plate making, effective correction, and proper preservation for successful printing operations. The teacher encourages students to practice these skills.

Pupils’ Activity: Students listen and prepare for the next lesson.

Learning Point: Plate making significance

Continuous Assessment/Further Study

Type: Homework

Instruction: Answer the following questions in your notebook:

1. Outline the complete process of making a conventional offset printing plate, from artwork to finished plate.
2. Research and explain the difference between conventional plate making and Computer-to-Plate (CTP) technology.
3. Identify and describe two potential problems that can arise during plate making and how they can be avoided.

Lesson Keywords

• Plate Making – The process of transferring an image from artwork onto a printing plate.
• Exposure Unit – A device used to expose pre-sensitized printing plates to light.
• Plate Developer – A chemical solution used to process exposed printing plates, revealing the image.
• Plate Gum – A solution applied to printing plates to protect non-image areas from oxidation and keep them water-receptive.
• Correction Fluid (Deleter) – A chemical liquid used to remove unwanted image areas from a printing plate.
• Plate Preservation – Techniques used to maintain the quality and extend the lifespan of printing plates for reuse.

Differentiation

For weaker learners, the teacher will provide simplified diagrams of the plate making steps and offer more guided practice during the correction and preservation demonstrations. Faster learners can research advanced plate making technologies like CTP or explore different types of printing plates and their specific handling requirements.

Suggested Lesson Videos

Search on YouTube for: “Steps in offset plate making” or “Printing plate correction and preservation”

Teacher Guide for Using This Lesson Plan

Before the lesson, ensure all instructional materials, especially the pre-sensitized plate, developer, gum, and correction fluid, are readily available and in good condition. Prepare a sample plate with a simulated error for the correction demonstration. Begin by clearly outlining the steps of plate making, using visual aids to support your explanation. During the demonstration of plate exposure, developing, and gumming, emphasize safety precautions, especially when handling chemicals. Guide students closely as they observe and practice correction and preservation techniques. Encourage questions throughout the lesson to check understanding. The Board Summary should be copied by students during Step 8. Conclude by reinforcing the practical importance of these skills in the printing industry.