Colour Management in Flexo Printing: Guide to Crack Colour Code

The colours in Flexo printing often differ from the colours displayed on the digital screen. The difference occurs due to dissimilarities in the colour models. The computer uses the RGB colour model, whereas Flexo printing typically uses the CMYK colour model. To bridge the gap of colour fluctuation, colour management in flexo printing is introduced. But what is this, and how does it help to get a vibrant and detailed printed image? We will know in this comprehensive blog post. Keep learning!

A] What is Colour Management in Flexo Printing?

Colour management is a crucial process in Flexo printing to achieve consistent and accurate colour reproduction across different printing conditions. It involves a series of processes, including calibration, characterisation, conversion, and control. Flexographic colour management ensures that the print runs depict brand consistency across different print jobs, leading to client satisfaction. Colour management in Flexo printing differs from other printing processes, such as offset and digital printing, due to its reliance on flexible photopolymer plates and anilox rollers. Together, it offers a different approach to colour management and calibration.

B] Key Elements of Flexographic Colour Management

1. Colour Standards & Profiles

Colour standards and profiles are crucial elements of Flexographic colour management as they ensure consistent and accurate colour reproduction across different devices and substrates. They provide a set framework for translating colours from screen devices to printing devices. The colour standards and profiles include ISO 12647 or G7 and ICC profiles, respectively. ISO 12647 and G7 are used in conjunction to achieve consistent colour reproduction, colour calibration, and grey balance in printing. On the other hand, the ICC (International Colour Consortium) profile is a translating tool to achieve consistent colour reproduction between monitor and printer.

2. Ink Density & Tone Value Increase (TVI)

Ink density and tone value increase (TVI) play a crucial role in colour management as they determine the behaviour of inks and their impacts on printed copy. Ink density quantifies the amount of ink deposited on the substrate. It ensures that a balanced amount of ink is deposited on the substrate, as high ink density darkens the colour and details, while low ink density produces light or washed colour. On the other hand, tone value increase (TVI), also known as dot gain, is a printing phenomenon where halftone dots (dots used in the printing process) in a printed image appear larger than their intended size. It causes the image to be blurred and less detailed. It requires optimisation of ink viscosity, plate pressure, and substrate characteristics to minimise TVI in the printed image.

3. Substrate Influence

The material or substrate that is being used for printing directly influences the accuracy of colour, which further affects the print quality. Different substrates, such as paper, metal films, and foils, react with ink differently, which leads to different print outcomes for different substrates. Therefore, it requires a substrate-specific proofing method or substrate-specific profile to match the colour accuracy based on the substrate characteristics.

4. Lighting & Viewing Conditions

Lighting and viewing conditions play a vital role in achieving consistent colour reproduction. The suitable lighting and viewing conditions are prepared through integrating ISO-compliant lighting devices (e.g., D50). It helps evaluate colours and accurate colour matching.

5. Calibration of Equipment

In flexographic colour management, precise equipment calibration is essential to maintain consistent and accurate colour output. This process uses tools, such as spectrophotometers, to capture the spectral reflectance of printed colour samples. The collected data is then analysed using profiling software to generate ICC profiles, which mathematically represent the colour characteristics of the printing device. These profiles help ensure accurate and consistent colour reproduction across the entire print production process.

C] Colour Standards and Profiles

Colour standards play a vital role in flexographic printing for ensuring consistency across different substrates and print runs. Pantone Matching System (PMS) provides universally recognised spot colours, while ICC profiles help calibrate devices for accurate colour reproduction. G7 methodology is often used to standardise grey balance and tonality. Delta E (ΔE) is a key metric to measure colour difference, where a lower value indicates a better colour match; typically, ΔE ≤ 2 is acceptable in packaging and labels. Commonly used colour spaces includeCMYK for print, RGB for digital displays, and LAB for device-independent, precise colour measurements.

D] Best Practices for Flexo Printing Colour Reproduction

1. Profiling The Press For Accurate Reproduction

Press profiling is important for accurate colour reproduction. It involves calibrating the press, using colour measurement instruments, and establishing effective communication protocols. Press profiling also reduces dot gain and aids in achieving a closer match between the digital image and the printed image.

2. Regular Colour Audits and Press Calibration

Routine colour audits and consistent press calibration are essential to maintain accurate and repeatable colour output. Use spectrophotometers to verify colour values and recalibrate the press as needed to reduce colour shift. Regular audits help detect issues early, ensuring consistency across multiple runs and substrates.

3. Use of Digital Proofing and Colour Targets

Digital proofing allows you to preview final print colours before production, minimising errors and costly reprints. Colour targets such as Pantone references and ICC-certified charts help align proofs with press output. Implementing these ensures colour expectations are communicated and achieved.

4. Training the Pressroom Team

A well-trained team is key to consistent colour reproduction. Operators should understand profiling, measurement tools, and process control techniques. Ongoing training ensures staff can troubleshoot colour issues and maintain the standards set by your colour management workflow.

E] Common Mistakes and How to Avoid Them

1. Ignoring Substrate Differences

Different substrates absorb ink differently, which can significantly affect colour appearance. Always test and profile the press for each type of material to ensure accurate results.

2. Skipping Prepress Calibration

Neglecting prepress calibration can lead to colour mismatches between the design file and the final print. Use calibrated monitors, standardised lighting, and regularly updated ICC profiles to ensure proper colour communication.

3. Not Monitoring Environmental Conditions (Humidity, Temperature)

Temperature and humidity can impact ink behaviour and substrate response, leading to colour shifts. Maintain controlled pressroom conditions and monitor environmental factors to ensure stable colour results across shifts and seasons.

Conclusion

Colour management in Flexo printing is a crucial process that effectively matches digital colours with printing colours. Follow the best practices and avoid mistakes to get a vibrant, detailed, and vivid printed image through the Flexo printing colour management process. Since 1990, NBG has been a trusted name in manufacturing and supplying top-quality Flexographic printing machinery to clients across India and around the world. With a proven track record of delivering advanced printing solutions, we are here to help you elevate your printing operations. We are one of the topprinting machinery manufacturers and our flexo printing machines are known for providing the utmost colour accuracy.Contact us now.

FAQs

What is colour management in flexographic printing, and why is it important?

Colour management in flexographic printing refers to the process of controlling how colours are reproduced throughout the print workflow to ensure consistency and accuracy. It is important because flexographic printing involves various variables such as substrate type, ink formulation, and press settings, all of which can impact colour output.

Can colour management help reduce print waste?

Tools and technologies used in flexo colour management include spectrophotometers for measuring colour data, densitometers, and ICC profiling software that creates device-specific colour profiles. G7 calibration methods and Pantone colour guides are also commonly used for standardisation.

Can colour management help reduce print waste?

Yes, colour management helps reduce print waste by minimising trial-and-error during press runs, reducing make-ready time, and ensuring accurate output from the start. This leads to cost savings and better efficiency.

Do I need special software or equipment for colour management?

Special software and equipment are typically required, including colour management software, calibration tools, and compatible RIPs. These tools are essential for achieving high-quality and vibrant colour in flexographic printing.