“Develop success from failures. Discouragement and failure are two of the surest stepping stones to success.”
Quality Control in Printing
Unit - 1
Definition: ‘Meeting the requirements of the customer.
According to ISO 9001:2008, “quality is the degree to which a set of inherent characteristic fulfills requirements”.
There are five aspect of quality:
1. Producing: providing something.
2. Checking: confirming that something has been done correctly.
3. Quality control: controlling a process to ensure that the outcomes are predictable.
4. Quality management: it optimizes its performance through analysis and improvement.
5. Quality assurance: obtaining confidence that a product or service will be satisfactory
Quality control: the observation technique and activities used to fulfill requirement for quality. Customer demand high-quality print jobs without variations or defects.
Control: an evaluation to indicate needed corrective response and change cause.
Quality assurance: describes any systematic process for ensuring quality during the successive steps in developing a product or service.
ISO 9000 is a standard for ensuring that a company’s quality assurance system follow best industry practices.
Quality assurance: the planned and systematic activities implemented in a quality system so the so that quality requirement for a product.
Assurance: the act of giving confidence, the state of being certain or the act of making certain.
Quality control & quality assurance
Product
process
Reactive
proactive
Line function
staff function
Find defects
prevent defects
Process control: Refers to the methods that are used to control variable such as proportion of one ingredient to another, the temperature of material, how well ingredient are mixed.
1. Reduce variable
2. Increase efficiency
3. Ensure safety.
Quality control process: quality is the key element in every stage of the production process form raw material to finish product.
Eight elements quality control process:
a. Ethics: ethics is a value based on hard work. Personal sincerity.
b. Integrity: morals, values, fairness, honest and sincerity.
c. Trust: trust at client and workers.
d. Training: provide appropriate training.
e. Teamwork:
f. Leadership: leadership does not only refer to top management. It is found at all levels and workers need to be guided by leader.
g. Communication: three direction
G (1) downward: top management to employees.
G (2) upward: where workers provide management.
G (3) sideways: supplier and customer.
h. Recognition: team should have their efforts ideas, and achievement and increase productivity.
These all element divided into four group:-
1. Foundation: ethics, integrity and trust.
2. Building: training, teamwork, leadership.
3. Binding martar: communication
4. Roof: recognition.
Steps of process management:
1. Evaluation:
a. Process for improvement.
b. Define the role responsibilities of the team member
c. Identify process goal.
2. Identify the stakeholder:
a. Requirement from the process.
3. Describe the current process:
a. Current performance.
4. Measure the process:
5. Identify blockage and barriers:
a. Apply problem solving technique
6. Root cause:
a. Source of every identify barriers.
7. Develop solution and implementation plan:
Quality circle: A quality circle is a volunteer group under the leadership, who are trained to identify and solve problem and present solution and become self-managing having gained the confidence of management.
Definition of Quality
Quality in printing is defined as:
“The degree to which a printed product meets specified requirements, customer expectations, and industry standards consistently.”
Key Points:
Quality Control (QC)
Definition:
Meaning:
Objectives of Quality Control:
1. Ensure printed products meet customer and industry standards.
2. Reduce rejects, reworks, and waste.
3. Maintain consistency in color, print registration, and finishing.
4. Ensure efficient use of materials and resources.
5. Prevent financial loss and reputational damage.
Functions of Quality Control:
Components:
1. Prevention Cost: Training, process design, preventive maintenance
2. Appraisal Cost: Inspections, testing, quality audits
3. Internal Failure Cost: Rework, scrap, downtime
4. External Failure Cost: Customer complaints, returns, warranty claims
Economic Consideration:
Features:
Key Activities in QA:
Feature
Quality Assurance (QA)
Focus
Process
Nature
Proactive
Objective
Detect defects
Prevent defects
Methods
Inspection, testing, sampling
SOPs, audits, training, process design
Timing
During/after production
Throughout the process lifecycle
Outcome
Rejects reduced
Continuous quality improvement
1. Consistent Print Quality: Accurate colour, registration, and image fidelity
2. Customer Satisfaction: Reliable products increase trust and brand value
3. Reduced Waste: Early detection of errors minimizes paper, ink, and substrate waste
4. Cost Savings: Fewer reworks, rejects, and complaints
5. Process Improvement: Insights from QC help optimize workflows and press performance
6. Regulatory Compliance: Ensures standards are met for packaging and publishing
7. Enhanced Reputation: Reliable and high-quality output improves market position
UNIT-2
Total quality management: It is a set of systematic activities carried out by the entire organization to effectively and efficiently achieve company objectives so as to provide products and service with a level of quality that satisfies customers, at the appropriate time and price.
A. Systematic activities: planned, strong leadership, mid and long term version, strategies and policies.
B. Entire organization: everyone at all levels, across functions.
C. Effective and efficient: achieved planned result with least resourced.
D. Quality: usefulness, reliability, safety.
Element of TQM:
1. Focus on customer (internal and external).
2. Involvement of the entire printing organization.
3. Requires a team effort (support).
4. Empowering employees: improve quality, productivity and take decision quality and change material, procedure, equipment and doing the job more effectively.
5. Mind set for process improvement.
6. Benchmark for process improvement all areas include marketing, sales, billing, training, maintenance.
7. Partnering with supplier and customers.
2. Statistical process control (SPC): it is a method for monitoring, controlling and ideally, improving.
The process can make as much conforming product as possible with a minimum waste (rework or trash).
It approach to resolving problem and do any type of measurement to help gather information and find a solution.
Purpose:
1. Prevent rather than detect defects.
2. Indicate the need for corrective action.
3. Continuous monitoring of the printing process.
4. Proof of quality.
5. Identify the source of variation.
6. Determine process capability.
Statistical process control tools:
1. Cause and effect diagram: fish bone diagram. It also called “Ishikawo diagram”.
It tree-like structure result showing the many facets of the problem.
2. Check sheet: it is a sheet or form used to record data.
Types of check sheet:
a. Production process distribution.
b. Defective item check sheet.
c. Defect location check sheet.
d. Defect cause check sheet.
e. Confirmation/inspection
3. Flow diagram: it are used to assist in systemically breakdown the organization process into step by step picture of each component. Symbols are used to indicate activities, decisions, beginning and ending point.
4. Pareto analysis: categories of problem graphically. That can be improved, such as the number of defective products, time allocation or cost saving. It indicate problem. It is based on principal 20% of the source cause 80% problem.
5. Histogram: you can put the data from the check sheet into a histogram, a snapshot of the variation of a product or the result of a process.
It helps you analyze what going on in the process and show capability of a process.
6. Run chart: display the variation in a process over time. The run chart displayed an average line taken the date. It is most used in printing to plot events overtime. Some include sales calls per months, completed jobs per weak, estimates per week, ink density per job and customer complaints.
7. Control chart: it is the best tools for monitoring the performance of a process.
Quality control: Quality control has three department:
1. Incoming: check all income material.
2. Process control: check over floor.
3. Pre dispatch inspection: final checking before dispatch.
1. Incoming stage: Material inspection and testing.
before accepting paper check inspection all paper transit damage, shortage, delivery receipt and proper packaging and found problem for doing damage complaint and click photography and before store in placed, all packing should be repaired and taped.
Old stock first used and after new.
1. Maintained data sheet.
2. Report and verifying paper problems.
3. Complaint handling process.
Test procedure: for paper and paper board
1. Paper grain: when the paper contact on heated when it is curl parallel to grain direction.
2. Grammage: Grammage is defined as the weight/mass per unit surface area of paperboard. The S.I metric unit in which grammage is expressed in grams/square meter (gsm).
3. Stiffness:
4. Tensile strength
5. Tearing strength
6. Bursting strength
7. Folding endurance
8. Smoothness equal surface
9. Shade
10. Humidity
11. P.H
12. Bursting factor
13. Cobb
14. Thickness
15. Bulk
16. Moisture content
17. Printability
Practical knowledge
1. Paper: Aim: check out GSM of paper according to requirement.
Sampling: draw out sample randomly as per sampling plan for paper and paper board.
Check sheets of 1-2 packets/pallets visually for loose particles, specks, spots, smoothness of top and back surface etc.
Test procedure: testing of paper and paper board should be done as per following.
Grammage: grammage is defined as the weight/mass per unit surface area of paper board. The S.I metric unit in which grammage is expressed in Grams/square meter (GSM).
Significance: most of paper is sold in accordance with its grammage and therefore grammage has great significance both to the consumer and the procedure in defining price. The value of many physical properties such as bursting strength, thickness and bulk interpreted and specified with regarded to grammage.
Apparatus: a weighing scale. It is a special sheet weighing device designed to weight test speciman of 500 square cm (i.e. 20cmX25cm) area current, when it is in use.
1. Template for preparing test speciman (20X25cm size).
2. A sharp cutting.
3. A hard surface such for cutting the sample.
Sampling & test speciman:-
1. Sampling to be done as per sampling plan shown as above.
2. Cut atleast 8-10 pieces of 25cmX20cm size from test speciman (1 each from no. of sample board taken) with the help of the template.
Procedure: check grammage one by one on the weighting scale.
Formula in CM: weight X 10000 / length X width.
Weight: 1.67 X 10000 / 10 X 10
Weight = 167 gms.
Formula in Meter: weight / length X width.
Report: report the grammage as arithmetic means of the value of the test speciman cut in grams/square meter. The range of maximum to minimum (i.e. specification) is also to be reported.
Acceptance creteria: it the value of grammage tested is not within the standard specification range i.e +/-5%, then the lot is liable to rejection.
However, the lot may be accepted within same condition after taking approval from QA (incharge).
2. Stiffness test: it is unit milineuter meter (mnm).
Aim: to check for resist towards bending of paper.
Sampling: draw out flat surface samples form the sheets and cut the required MD & CD sample form that sheet by cutter.
Appratus: stiffness tester, weight box, cutter.
Sample size: length=7cm and width=3.8cm.
Significance: stiffness test is a very important test in board, since the utility of the box depends upon its ability to resists bulging when filled, packages must resists deformation or bulging, when being filled and when the contents settle in a package-folding cartons must also withstand bending stresses from loads imposed on them from containers stacked above.
Leveling: before starting the machine please ensure that all three pointers of pendulum, driving disc and stationery disc and zero. Leveling can be done with the help of leveling screws at the base of the stand.
Cutting of test strip: cut the test strip with the help cut shear, place the material to be cut at the back guage with an additional quick blow with the ball of the hand to detach strip form the sheet. Test smaple will be cut in 1 ½ “X 2 ¾ “size. Immediately mark the grain direction of the board to identify MD & CD.
Formula: Left X 5 + right X 5 / 2.
Ex: 25X5 + 25X5 / 2.
125 + 125 /2 = 250/2 = 125
Operating the instrument: we know strip insert in jaws in marked and down mark according roller only contact not pressure cause pendulum move and the slowly move the roller ¼ turn in reverse direction same procedure R.H.S and put a calibrated range weight on the lower pendulum stud. For 500 unit different range. The mark on the pendulum aligns to the 7 ½ or 15 degree mark on the driving disc. If pointer mark 25 note the reading as 25X5=125 for range weight of 1000 unit the reading will be 25X10=25 taber unit.
Acceptance criteria: stiffness reading should be within 10% of the specified stiffness values.
3. Thickness (dial thickness guage):
Scope: this method described the procedure for measuring single sheet thickness and variation in single sheet thickness and combined board expect for kraft paper.
Definition: thickness of caliper of paper/ paper board as measured by this method is defined as the perpendicular distance between the two principle surface of the paper board under pressureribed conditions.
Significance: variation in thickness can create lots of problems during printing and punching of cartons. The print transfer form blanket to surface will be improper. The crease will be shallow at some place and deep at other place. Variation in thickness may be resulted into rough cutting problem during punching.
Apparatus: a handy dial thickness gauge having 1cm or 0.01mm least count.
4. Surface PH:
Definition: PH is inverse of logarithmic hydrogen ion concentration of the surface of paper.
Significance: it is non-destructive test for finding out the PH of paper which has a direct relation with the life of paper. A PH of 5.0 to 6.5 is widely accepted and a very high low PH can adversely affected the printing and also the life of paper.
Apparatus: a universal PH indicator solution is available from heading lab reagent manufactures like qualigence, glaxo, S.D, fine chemical.
5. Size:
Definition: distance between two edges.
Longer side = length
Shorter side = width
Significance: variation in size will be resulted into out printing and out punching problem. Variation in width at minus side will create grip problem at the feeder of the printing machine and also complete form blanket will not be transfer as sheet is smaller in size variation in length with create feeding problem on machine and also side lay.
6. Moisture content:
Definition: the percentage of the part of water in board in normal condition called moisture.
Calculation:-
a. Weight of empty beaker (a) = --------------------- gms.
b. Weight of beaker + substrate (b) = -------------------gms.
c. Weight of substrate (c) = (b-a) = ------------------------ gms.
d. Weight of beaker + substrate (after heater) (d) = ---------------------gms.
e. Weight of moisture loss during heating (e) = (b-d) = ------------------------gms.
% moisture content = E/C X 100.
7. Cobb value: Cobb value is defined as the mass of water absorbed by the unit area of paper in time specified.
Significance: sizing bigger and smaller and high consumption ink and adhesive.
Cobb formula
A = without moisture paper GSM.
B = after moisture paper GSM.
(B – A) X GSM = ------------------------- g/m2.
8. Printability:
Definition: board’s ability to give good print quality with the help of various properties of board is printability of board.
Significance: the degree of surface property is same level and high print quality by a particular printing process. Surface properties are smoothness, levelness and uniformity with which the surface accept ink transfer and absorption of ink.
Defects: hickies, unwanted spots and checks on the printed area
Picking: this defect can appear to poor bonding between the two layers of the pulp.
9. Busting strength:
AIM: check for maximum pressure withstand by the spiceman.
Sample size 10X10cm
Unit: kg/cm2
Apparatus: bursting strength tester.
10. Bulk: formula – thickness/GSM.
11. Bursting factor (B.F):
B.S / GSM X 1000
kg/cm2 / gm/cm2 X 1000
12. FET: folding endurance test = with 2 folds
13. Scuff tester: unit is RPM (rotation per minutes)
Purpose: to lay down the work instruction for scuff testing.
Scope: this procedure is applicable to all printed items to ensure minimum scuff property required/ specified by the customer.
Responsibility: quality control inspector.
Instruction:
a. Sample area down form the printed board or cartons as per standard practice.
b. Prepare sample, cut 2 disks of 2” and 41/2” diameter form printed sheets with the help of circular template.
c. 41/2” sample is placed blew the ring and 2”diameter sample is fixed to the bottom side of metal disk with the help of double side tape.
d. After placing the sample pull the back knob this will rotating shaft move on downwards and smaller sample contact with the larger sample.
e. Press the main switch (red color) for power on.
f. Check digital counters shows 00000 if not press & hold the reset button about 2-3 seconds. Now counter is shows 0000.
g. On the thumb wheel, select the number of rubs.
h. For aqueous coating: select 250 rubs.
1. For UV coating: select 500 rubs.
2. Scuff load pressure: 2 lbs.
i. Now press the green start button. Both the top and bottom sample disks start rotating in same direction. The green light indicted processes on and blower is also started simultaneously. Blower removes the particles of dust/paper/ink/from our printed sheets.
j. After desired number of rubes stops the machine red light will appear.
k. Observe rubbed surface to judge visual the scuff proof-ness of printed surface.
l. Write your observation in the report.
Adhesive Testing
Test procedure of adhesive
1. Sampling procedure: draw out about 250 ml of adhesive.
2. Solid content: solid part of adhesive, excluding water in water based adhesive and executing solvent in solvent based adhesive is called as solid content of adhesive.
Significance: adhesive must check because it affects the gluing capacity of the adhesive. Solid constitute functional part of any adhesive, as volatile part only wet carrier and absorbed by the substrate or gets evaporated.
Formula; weight of empty tin = (a) = ------------------- gms.
Weight of tin + adhesive = (b) = ----------------------- gms.
Weight of adhesive = (c) = (b-a) = ---------------------- gms.
Weight of tin + solid adhesive (after heating) = (d) = ------------------------- gms.
Weight of solid adhesive (after heating) = (e) = (d-a) = ------------------- gms.
= fevicol weight after dry/before heat fevicol weight X 100
% of solid content = e/c X100
(d-a) / (b-a) X 100 = --------------------------- % weight.
3. Viscosity: the resistance of an adhesive (fluid) to shear force.
Significance: the flow of properties of the adhesive are out-most important when it is used for lamination adhesive in substrate.
4. PH: logarithmic concentration of hydrogen ions. (The molar concentration of H+ ions).
Significance: PH adhesive should be around neutral 5 to 8. A PH less 5 and more 8 may ultimation dis-coloration of print after reaction.
Varnish Testing
Sampling required: 250 ml of varnish any one drum.
1. Solid content: in water-based varnish, solid part of varnish excluding water is called as solid content.
Significance: solid content must be check because it affect the coating capacity of the varnish. Solid constitute the function part of any . , as volatile part only acts as a carrier and either gets absorbed and evaporated.
a. Whether the solids are within the limits specified by the supplier or not.
b. To compare the price of the same type of material supplied by two different manufacture.
c. Whether the solution requires further dilution or it can be taken directly on machine.
Calculation:
Weight of empty tin = (a) = ------------------------ gms.
Weight of tin + varnish (b) = ------------------------ gms.
Weight of varnish = (c) = (b-a) = --------------------- gms.
Weight of tin + solid varnish (after heating) = (d) = --------------------------- gms.
Weight of solid varnish = e = (d-a) = ----------------------- gms.
% solid content = e/c X 100
(d-a) / (b-a) X 100
= ------------------- % weight.
2. Viscosity: the resistance of a varnish (fluid) to shear forces.
Significance: the flow of properties of the varnish of most of outmost important because it is used for coating process by keeping proper viscosity adequater amount of varnish.
Apparatus: we check viscosity varnish by ford cup method, with B4 as per ISSPE 3944. The office of B4 cup is of 4mm diameter.
250ml glass beaker.
Glass rod.
Varnish sample.
Sampling: take 100 ml varnish from the varnish sample taken above.
3. PH: 5 to 7.5 (glaxo)
Sampling procedure: sampling of liner should be done as per sampling plan for LINER reference.
1. Size: for liner the distance between two edges of the film at short side. The width of the film while it is in roll form is defined as size of film.
Significance: if the width (size) of the film is less than ordered size then it will be resulted into short lamination and if the width of film is more than ordered size then it will be resulted into full lamination it will cover also the pasting flap of cartons and that will create pasting problem.
2. Corona treatment: corona treatment is a treatment given to the BOPP & polyester films to get wetting tension and corona treatment test is done to measure such wetting tension and this test shows treatment level achieved by the surface of plastic film.
Significance: BOPP & polyester film being a non-polar substance, do not allow the liquids to spread on it. BOPP & polyester film used for lamination must be treated so that they allow the adhesive to spread. The film should be treated is to adequate level so that it becomes receptive to adhesive. The treatment is given by passing the film through high voltage discharge.
Apparatus: difference no. corona treat tester pens along with refill pack of their relevant numbered test fluid. We use 32, 34, 36, 38, & 40 no pens which shows treatment level in 32, 34, 36, 38, & 40 dyns/cm2.
3. Visual inspection: observation of the film rolls from all the angels (for wrinkles, for handling damage, for winding, flash cut, for roll no. on core of the roll etc.) is the visual inspection of film roll.
Significance: visual inspection of the film roll is to be done to see that if there are wrinkles or any kind of handling damage or paper winding of film roll is there or not because it affects the actual lamination process. Also check the roll no. on the box and on the care of that roll are same or not, also check the box no.s and roll no. are as per the packing list supplied by the supplier or not, because it’s useful to uniform the supplier while some rolls are rejected due to problem faced during production.
CFC Testing
Theory= 30% extra semi kraft than virgin kraft upper and last layer called virgin and between semi kraft
Virgin kraft standard = 140 GSm
Semi kraft standard = 130 GSM
Liner GSM (flat) = total gsm / 130 X 100
Total GSM = 180 / 130 X 100 = 37
Actual GSM = 160-37 = 123.
UNIT-3
A Quality Control Programme ensures consistent, high-quality output throughout all stages of printing. It involves systematic inspection, testing, and process monitoring in every department. Proper QC reduces waste, enhances customer satisfaction, and improves efficiency.
QC Focus: Accuracy of files, layouts, and plates.
QC Measures:
Equipment / Tools: RIP software, colour management systems, densitometers, calibrated monitors.
QC Focus: Colour accuracy, registration, print density, ink coverage, and substrate handling.
Equipment / Tools: Spectrophotometers, densitometers, colour bars, inline quality monitoring systems.
QC Focus: Cutting, binding, lamination, embossing, varnishing, and packaging.
Equipment / Tools: Measuring tools, inspection tables, magnifiers, finishing presses.
QC Focus: Durability, print quality, registration, and compliance.
Equipment / Tools: Adhesion testers, barcode scanners, spectrophotometers.
QC Focus: Raw materials and finished goods storage conditions.
Equipment / Tools: Hygrometers, temperature monitors, inventory management systems.
QC Focus: Accurate orders, correct quantities, and delivery standards.
Tools / Systems: ERP systems, barcode scanners, tracking software.
1. Define Quality Standards: Based on customer requirements, industry standards, and regulatory norms.
2. Develop QC Checklists for Each Department: Specific to prepress, press, finishing, packaging, and dispatch.
3. Train Staff: Ensure employees understand QC procedures, tools, and responsibilities.
4. Implement Monitoring & Inspection: Regular checks during all stages of production.
5. Document & Record Data: Maintain inspection reports, deviations, and corrective actions.
6. Continuous Improvement: Analyze QC data to identify trends, reduce defects, and optimize processes.
7. Audit & Review: Periodically review QC programme for effectiveness and update procedures as needed.
What is ISO: (international organization for standardization) international standard give state of the art specification for products, services and good practice, helping to make industry more efficient and effective. They help to break down barrier to international trade.
What we do: food safety to computers, and agriculture to healthcare, ISO international standards impact all our lives. It is covering almost all aspects of technology and business.
The cycle of management:
a. Plan:
1. Establish your objectives.
2. Make plans
2 (a) analyze your organization situation
2 (b) establish your overall objectives
2 (c) set your targets
2 (d) develop plans to achieve them.
b. Do: implement your plans.
c. Check: measure your results
d. Act: correct and improve you plans and how put them into practice.
Implementation of ISO for print quality
Introduction: ISO 9001:- ISO 9000 is a series of standard develop and publish by the international organization for standardization (ISO), that define, establish, and maintain an effective manufacturing and service industries.
ISO 9001:2008 quality management system certification enable you to demonstrate your commitment to quality and customer satisfaction, and continuous improving your company.
It improve quality, expanding trade, increasing productivity, lowering costs, and transferring technology around the globe.
Background: in November 2008 the (ISO) introduced a revised QM standard based on same 2000 revision with emphasis on measuring customer satisfaction. The current version continues to compatibility with ISO 14001 environment management system.
ISO 9001 group have 4 categories:
1. Management: goal, planning & objective, review program.
2. Resources: people, tools, equipment.
3. Service or product ‘realization’: creating or delivery them.
4. Monitoring, measure & checking: all feedback loop.
Benefits ISO 9001:2008
1. Establishes complete documentation.
2. Improves training processes.
3. Provides advantages over competitors that aren’t certified ISO 9001:2008.
4. Opportunities for global commence with international recognition.
5. Production standard improves.
6. Provides for regular audits/review of performance.
Step involved in ISO 9001 certification:
1. Gap analysis: quality management practice vis- a -vis ISO 9001 requirement.
2. Orientation training: requirement and action plan.
3. System documentation: preparation of quality manual and design of quality record format.
4. System implementation: implement of quality system.
5. Company-wide training: statistical quality control technology housekeeping (Japanese 5-S), and quality audit.
6. Internal quality audit.
7. Pre assessment: initial audit by certified agency.
8. Final assessment: recommendation for certification.
ISO philosophy:
1. What you do: work flow.
2. Do what your document: need document.
3. Give the customer: check the result, inspection and correct the difference.
ISO 9001 series
1. ISO 8402: quality management and quality assurance vocabulary.
2. ISO 9000: guidelines for selection and use
3. ISO 9001: model of quality assurance design, develop, production, installation and servicing.
4. ISO 9002: quality assurance production, install and service.
5. ISO 9003: quality assurance final inspection and test.
6. ISO 9004: quality management and quality system element.
7. ISO 10011: guidelines for auditing quality system.
8. ISO 10012: requirement for measuring equipment.
9. ISO 10013: guidelines for quality manual.
ISO 12647 series: it is printing method for use.
1. ISO 12647-1: parameters & measuring methods.
2. ISO 12647-2: offset.
3. ISO 12647-3: Cold-set offset for newspaper.
4. ISO 12647-4: publication gravure.
5. ISO 12647-5: screen printing.
6. ISO 12647-6: flexography.
7. ISO 12647-7: proofing process form digital data.
8. ISO 12647-8: digital printing.
Current standard for printing and media:
1. ISO 2846-1: which ink color and transparency.
2. ISO 3664: lighting condition for view color.
3. ISO 15930: X (pdf/X): data exchange in print production.
4. ISO 15076: ICC (color profile format).
5. ISO 12640: data format for which ICC profile are calculated.
ISO (International Organization for Standardization) develops international standards to ensure quality, safety, efficiency, and environmental sustainability across industries.
Key Features:
Applications in Printing:
System
Definition
Purpose in Printing
QMS
Framework for managing quality
Ensures consistent print quality, customer satisfaction, and process efficiency
EMS
Framework for managing environmental impacts
Minimizes waste, energy consumption, and environmental footprint in printing operations
Key Parts Relevant to Printing:
Applications:
Common Tests and Instruments:
Test
Instrument
Purpose
Grammage (weight)
Grammage tester
Measures paper weight per m²
Thickness / Caliper
Micrometer / Thickness gauge
Ensures proper thickness for printing and packaging
Smoothness
Bendtsen Smoothness Tester
Measures surface smoothness affecting ink transfer
Porosity / Air Permeability
Gurley Tester
Determines ink absorption rate and print sharpness
Opacity & Brightness
Opacity / Brightness meter
Ensures readability, print contrast, and colour fidelity
Tensile Strength
Tensile tester
Checks mechanical strength for packaging
Print Gloss
Glossmeter
Measures sheen for visual quality
Ink Absorption / Cobb Test
Cobb Tester
Determines water/ink absorption capacity for printing
Importance:
Unit – 4
Ink testing ensures that inks meet optical, working, and end-use requirements, maintaining consistent colour and performance.
Purpose / What it Measures
Spectrophotometer
Measures optical properties like colour density, hue, and colour consistency; essential for colour matching
Densitometer
Measures optical density (OD) of ink on press sheets; monitors tonal values and density curves
Viscometer / Zahn Cup
Measures viscosity of ink; ensures proper flow, transfer, and drying characteristics
Measures surface gloss of ink film on printed substrate
Drying Tester / Ink Tack Meter
Measures ink drying time and tack, important for multi-colour overprinting
pH Meter
For water-based inks, checks acidity/alkalinity affecting substrate and press performance
Adhesion Tester / Tape Test
Checks ink adhesion on paper, board, or other substrates
Printability Test Instruments
Includes test presses or drawdown devices for evaluating ink spread, colour strength, and drying properties
Process control instruments monitor press conditions during multi-colour printing to ensure consistent quality.
Instrument / Device
Function
What it Measures
Control Strips / Colour Bars
Printed on sheet edges
Ink density, dot gain, tonal range, trapping, colour balance
Spectrophotometer / Inline Colorimeter
Continuous monitoring
Colour accuracy, grey balance, CMYK density
Spot measurements
Optical density of individual colours
Registration / Alignment Devices
Mechanical or optical
Accurate positioning of multi-colour plates
Moisture / Humidity Sensors
Monitor environmental conditions
Paper and ink behaviour consistency
Tack / Ink Film Thickness Meters
Inline measurement
Ink transfer, drying, and print sharpness
Features Measured:
How it Works:
Examples & Functions:
1. Inline Colour Measurement Systems (e.g., X-Rite, Techkon) – Real-time CMYK density and colour control
2. Registration Sensors – Monitor plate-to-sheet alignment
3. Moisture / Substrate Sensors – Detect paper swelling, curl, or tension issues
4. Dot Gain Measurement Tools – Ensure accurate tonal reproduction
Principle:
For producing multi-colour printing jobs at an appropriate quality level:
This minimal set ensures consistent colour, registration, and print quality, even for high-volume production.
Optical density, colour matching, grey balance
Spot optical density measurement
Dot Gain Comparator
Checks dot reproduction for halftone accuracy
Measures gloss variation across prints
Adhesion Tester
Measures ink-substrate adhesion
Drawdown Plates / Test Press
Evaluates ink spread, drying, and printability
Standards for Print Quality:
Typical Tolerance Guidelines:
1. Ink testing instruments ensure optical and working properties are consistent for multi-colour jobs.
2. Process control devices and QC strips monitor production in real-time for colour, registration, dot gain, and tonal consistency.
3. Minimal instrumentation (densitometer/spectrophotometer, registration sensors, control strips) can maintain high-quality production.
4. Adherence to ISO standards, G7 specifications, and tolerances ensures consistent, professional print output.
4.2 SPECTROPHOTOMETERS
Working principle of Spectrophotometers:
1. Place the spectro on the sample and click the button to measure.
2. The spectro projects a light onto the sample’s surface.
3. The sample absorbs some of the light and reflects the rest into a set of filters.
4. The spectrophotometer measures that reflected light at many different points to capture the fingerprint, or signature, of the sample and presents it as a reflectance curve.
5. The reflectance curves of samples can be compared to the reflectance curves of standards to determine even the most minute color differences.
6. This is how manufacturers determine whether the color they’re producing is on target.
Basic components:
1) Light source
Spectroscope
Optics
Detector
REFLECTANCE CURVES
3. Analysis of Print Attributes
1) Solid Ink Density (SID)
2) Dot gain
Z (%) = FD – FF
Here are some other factors that cause dot gain:
1. Ink and water balance.
2. Blanket construction or other properties.
3. Blanket height.
4. Roller settings.
5. Bearer pressure settings.
6. Plate wear.
7. Ink temperature.
8. Piling.
3) Print Contrast
K(%) = Ds – Dt x 100
Ds
1. Rolling and printing pressure,
2. Blankets and underlays,
3. Dampening Solution,
4. Printing inks and additives.
4) Ink Trapping
5) Dot Area
Colour difference - Delta E