Spectrophotometers in Print & Packaging

A spectrophotometer is an instrument that is used by printers to ensure that the colors they are printing are consistent with brand standards, across different locations, materials, and utilizing different printing processes. Spectrophotometers have the ability to measure Delta E, or the difference between 2 colors.

The spectrophotometer works by utilizing a white light source (LED or incandescent) that illuminates the desired measurement location and reflects light which is then separated by either a diffraction grating or narrow band filters.

In short, the spectrophotometer works by measuring the different wavelengths of light that are reflected off a printed sample.

Introduction to Spectrophotometry

Spectrophotometry has come a long way since its original development.

Spectrophotometers are now more accurate, more reliable, and more efficient, making them staple tools in many press rooms.

The SpectroDens, Techkon’s Spectro-Densitometer, combines the capabilities of a spectrophotometer and a densitometer, giving press operators all the information they need in order to complete print jobs in a timely and cost-friendly manner.

Purpose of Spectrophotometers in Print and Packaging

Color accuracy is important, and spectrophotometers are used in packaging and printing industries to determine the Delta E, or the difference between two colors. A spectro-densitometer, which is a device that combines the functionality of a spectrophotometer and a densitometer, is a tool that allows press operators to gain even more insight.

A densitometer is a device that measures the density of a printed sample. Spectrophotometers and Densitometers have different capabilities, but Techkon’s SpectroDens has the ability to do both. The SpectroDens measures density, as well as compares color.

Evolution of Spectrophotometry in the Print Industry

Spectrophotometry began in the 1940s. The concept was invented by Arnold J. Beckman at National Tecnologies Laboratories. Before the invention of the first spectrophotometer, analysis of color was a process that was very inaccurate and time consuming. The spectrophotometer took the accuracy from 25% to around 99%.

In 1981, Cecil Instruments developed a more advanced spectrophotometer that was more reliable and even faster. Since then, spectrophotometers have become a staple in the print industry, with their ability to efficiently measure color differentials.

How Spectrophotometers Work

Spectrophotometers were designed to determine Delta E, or the difference between two colors. A spectrophotometer works by capturing discrete spectrum amplitude values at 10 nm or 20 nm intervals. A white light source (typically either incandescent or LED) that is perpendicular to the printed sample illuminates the desired section.

The reflected light is then separated by narrow band filters, and the curve that results is an identifier or digital signature of the measured color sample. This data can then be converted into an industry color standard. The different wavelengths of light are reflected as a spectrum, which is made up of visible color.

Measuring Color Accuracy in Print Production

Accuracy is important in packaging, as consumers are likely to notice if the color of a package does not match what they have come to know the brand as. In print production, it is the job of the press operator to guarantee that the color of packaging is true to the brand’s color standards. Spectrophotometers allow press operators to measure the consistency as well as the accuracy of any print job.

Components of a Spectrophotometer

Components of a spectrophotometer include a light source, which illuminates the sample, optics which focuses the light on the sensor, and the detector, which picks up the reflected light.

Light Source

A light source is crucial for a spectrophotometer to function, as it illuminates the printed sample. In a standard spectrophotometer, designed for the graphic arts, the light source will hit the sample at either a 45 or 0 degree angle, and the reflected light will be picked up, or detected, at either a 0 or 45 degree angle respectively. A light source is either LED or incandescent, however Techkon devices use LED light sources as they tend to last longer.

Optics

The optics in a spectrophotometer focus the light on the sensor. This component ensures that the light is directed to the sensor.

Detector

The detector is the component of a spectrophotometer that picks up the reflected light. After the light source hits the sample at a 45-degree angle, the detector will pick up the reflected light off the sample at a 0-degree angle, to ensure that reflection from the graphic material did not impact the measurement.

Types of Spectrophotometers for Print and Packaging

Technological advancements in spectrophotometry have made the lives of printers much easier. Now, there are different variations of the devices that range from handheld, inline, automated, and closed loop, each with specific functions to benefit the user.

Handheld spectrophotometers are portable and can be transported easily. Inline spectrophotometers are guaranteed to ensure consistency and quality control, as little to no operator intervention is required due to the closed loop system.

Automated spectrophotometers are well suited for production settings, while closed loop systems remove the need for guesswork in color management.

Handheld Spectrophotometers

Portable spectrophotometers, also known as handheld devices, are perfect for a busy press room setting. Handheld, or portable spectrophotometers are Wi-Fi capable, which allows press operators to move around, without needing to keep the device attached to a computer or power source.

Techkon has a range of handheld devices, including the SpectroDens, SpectroPlate, SpectroDrive, and SpectroJet. The SpectroDrive and the SpectroJet are automated scanning spectrophotometers but can be used as portable spectrophotometers as well.

Inline Spectrophotometers (Used in Flexographic Printing for Real-Time Color Measurement)

Inline spectrophotometers are installed directly into a printed press, which increases accuracy and consistency while reducing waste. Techkon has developed three different inline solutions: SpectroEdge, SpectroView, and SpectroVision. The SpectroEdge can be integrated into a variety of digital printing engines. The device is highly accurate and can measure 3,000 samples per second.

This offers real-time measurements and closed loop control, without the need for press operator intervention. The SpectroView is favorable for industrial manufacturing settings. The measurement process is 100% automated, which means operators do not need to be skilled in using spectrophotometers to be able to use the device.

The SpectroVision is the world’s most innovative In-Line color management system, as it is compatible with Flexo, Gravure, and Digital, web presses. The SpectroVision shows real-time PASS/FAIL and color difference results, which significantly decreases make ready times.

Automated Scanning Spectrophotometers

Automated spectrophotometers are devices that are often stationary and are perfect for production and manufacturing style settings. Techkon’s SpectroDrive is an automated scanning spectrophotometer that runs on a precision track. The device can also be removed from the track and used as a handheld instrument for “spot check” measurements.

The SpectroDrive is reliable and efficient, as it can scan press sheet color bars in a matter of seconds. The SpectroJet is another spectrophotometer that runs on a track but can also be picked up for handheld measurements. This device is much more cost-effective and is very easy to set up. The MYIRO-9 is an auto scan spectrophotometer that has the ability to read 1,500 patches in 4 minutes.

The MYIRO-9 has the ability to measure a wide range of charts and targets, offering versatility and compatibility. The device is also equipped with a built-in wavelength calibration and temperature drift compensation to correct any issues that could impact color accuracy. For more information about other MYIRO products, visit our website.

Closed Loop Systems

PressLink is Techkon’s closed loop color management system that combines the Spectrophotometer and SpectroDrive with color control software. This software is installed with the press-side ink key console. The software moves the keys for the press operators, in turn removing the guesswork and reducing make ready times as well as waste.

Applications of Spectrophotometry in Print and Packaging

In print and packaging, spectrophotometry can help reduce waste, save money, and save time. These devices can be used for quality control, as well as ensuring accuracy and consistency across many different print jobs. Spectrophotometry takes the guesswork out of color comparison, as it can objectively determine if two colors are within a set tolerance. Handheld devices are great for spot checks, whereas automated scanning tools are perfect for production and manufacturing settings.

Print Quality Control

Quality control is vital in the printing industry. The longer a press runs without being “in color,” the more money and material is going to be wasted. By using a spectrophotometer to measure Delta E of a print job, operators are able to guarantee that the job is meeting color standards.

Ensuring Color Consistency Across Print Runs

Spectrophotometers help to ensure that colors remain consistent throughout all print runs. Handheld and automated devices allow operators to pull a job off of a press and measure samples to determine if the sample is meeting a company’s color standards. Inline solutions measure print samples as the press is running, and with the use of PressLink or ChromaQA with SmartINK, make adjustments to the ink without human intervention.

Meeting Brand and Industry Color Standards (G7, ISO)

In printing and packaging, it is important to make sure that the colors of a print job meet the brand’s color standards. If the job does not match what the brand desired, printers may have to re-print the entire job, which costs a lot of money and requires a lot of materials.

Meeting industry color standards, such as ISO and G7, is also important. Applying spectrophotometry devices to these jobs allows press operators to determine if the job is meeting brand as well as industry standards, within seconds.

Packaging Industry Applications

In the packaging industry, spectrophotometry can be useful when printing on different types of materials. The same color may appear different when printed on paper and cardboard, as cardboard is a corrugated material. Corrugated materials tend to absorb more light, in turn making a color appear darker. Devices, such as the SpectroDens, can be useful in determining if a job meets a brand’s color standards.

When searching for a spectrophotometer for packaging applications, it is important to think about factors such as the types of packaging materials, portability needs, as well as industry standards that need to be met.

Inline Color Measurement for Flexographic Printing

Inline color measurement is a cost-effective way to ensure that desired color quality is being met. Inline solutions, such as the SpectroVision make the measurement process 100% automated. This ensures that measurements will be taken at regular intervals and provides clear PASS/FAIL indications to the press operator. By reducing the chance of producing waste, printers can save time and money.

Controlling Spot Colors & Substrate Variations

Spot colors are easily measured with a spectro-densitometer. In the past, densitometers were not designed to accurately measure the density of printed spot colors, however the development of spectrophotometers has solved this issue. SpectroDens has the ability to seamlessly measure spot colors using “spectral” density. The spectral density is optimized for each spot color based on its unique spectral reflectance information.

As for substrate variations, spectrophotometer can be used to measure color on different printing or packaging materials. There are several types of spectro-densitometers that can be utilized for different types of materials. The traditional SpectroDens uses a light source that hits the sample at a 45-degree angle and detects reflected light at a 0-degree angle. SpectroDens also is also equipped with an optional polarization filters that make sure polarized light from wet ink can be measured accurately. Spectrophotometers with a spherical aperture can be used for surfaces that may be metallic, curved, or have a rough texture. The spherical aperture integrates reflected light from multiple angles to determine a Delta E measurement.

Pressroom Workflow Optimization

Optimizing your workflow means that your pressroom is running as efficiently as possible. This could mean that there is a reduced amount of waste, jobs are getting finished at a faster pace, and quality standards are still being met. Accurate color data and automated color adjustments can help operators reduce their make ready times.

Reducing Make Ready Time with Accurate Color Data

Data is extremely important when it comes to reducing make ready times. Data analysis allows operators to make informed decisions, rather than guessing. This allows operators to ensure consistency and repeatability with each job, whether on a different packaging material or at a different location. The less time that is spent adjusting ink, the faster a job will be completed.

Automating Color Adjustments with Spectrophotometry

With the use of tools such as PressLink, which combines the Spectrophotometer and the SpectroDrive with color control software, printers can get real-time insight about a job. PressLink automatically moves the keys on the press-side ink key console, which removes the need for a trained eye to determine ink adjustments.

Advantages and Limitations of Spectrophotometers in Printing

As all technology has its benefits and limitations, so do spectrophotometers. The automated devices allow press operators peace of mind, as they no longer need to rely on a well-trained eye to make decisions about color adjustments. Quality control is important to printers, and spectrophotometers remove the need for subjectivity in color analysis, ensuring consistency and quality. Furthermore, they offer clear feedback about how to meet color standards, which can reduce waste as well as make ready times.

Benefits of Using Spectrophotometers in Print and Packaging

Spectrophotometers allow press operators peace of mind, as they no longer have to rely on guesswork. Quality control is important, and with a handheld or automated device, press operators no longer need to rely on their eyes, as the device will measure color differentials instantly. Skill and years of training your eyes is no longer necessary, as the device can measure the sample objectively. Data collection is also crucial, as it allows businesses to make informed decisions. Spectrophotometers offer press operators feedback that they can implement in order to ensure they are meeting color standards across all printing locations and jobs. With automated scanning spectrophotometers, operators can reduce waste as mistakes can be caught very early in the production process. By catching these mistakes early, automatic scanning spectrophotometers can also shorten make ready times, as getting the press “on color” will be a much faster process. These automated devices are a great way to automate the color control process, as they can scan an entire press sheet in a matter of seconds.

Common Challenges and How to Overcome Them

Reflective materials, such as metallic coated labels, are a challenge for the typical graphic arts, 0/45 or 45/0 spectrophotometer. In order to get an accurate measurement, spherical geometry is required. This type of spectrophotometer uses a larger aperture and integrates light from multiple angles to ensure an accurate reading is obtained. A spherical spectrophotometer would be best suited for industrial applications or measuring rough surfaces such as textiles.

Another challenge comes into play when dealing with clear materials. It can be difficult to measure the color of a sample that has been printed directly onto clear packaging as there is no background to measure the sample against.

Choosing the Right Spectrophotometer for Your Print Business

Not all printers and press operators will have the same needs. Different brands and different print jobs will have a range of distinct requirements that need to be met. The press operator has the role of ensuring these needs are met, which is why it is important to consider what factors are important to your business and customers when choosing a spectrophotometer.

It is important to think about the type of material that packaging is made from, as certain materials will interact and reflect color in different ways. Printers should also think about the level of high precision and accuracy that is required, as no two jobs are the same. Finally, the budget is something that all businesses must consider, as investing in new devices can be costly.

Despite this, it is important to think about long-term benefits, and the money and time that could be saved.

Handheld vs. Inline Spectrophotometers

Inline spectrophotometers, such as the SpectroVision are a great fit for businesses working with industrial applications. These inline instruments require no human intervention, as it automates tasks. These systems work well when a more repeatable manufacturing process is taking place. On the other hand, handheld spectrophotometers are perfect for press operators who are looking for a device that can move with them. The SpectroDens is Wi-Fi capable and does not need to be connected to a computer to remain in communication with the device. These devices are easy to use, and are extremely durable, making them a great fit for a manufacturing environment.

Budget Considerations & ROI in Print Quality Control

Spectrophotometers can be expensive, but there are options that are more budget friendly. The SpectroJet, for example, is a spectro-densitometer that can be guided along a track but can also be used as a handheld device for “spot checks.” The SpectroJet is a lower cost solution compared to the SpectroDrive. This device utilizes Techkon ExPresso Software which offers a cost-efficient and easy to monitor an offset printing press. While budget considerations are important, it is also important to think about the cost of waste. Spectrophotometers save time and money, as they reduce the chance of re-prints. Each minute that a press is running with an incorrect color cost the printer money, ink, time, and substrate. Investing in a spectrophotometer can produce a high return on investment, as they can reduce waste as well as the time it takes to ensure accuracy and consistency in a print job.

Future Trends in Spectrophotometry for Print and Packaging

Spectrophotometry has come a long way since its original development in the 1940s, and there are still advances being made to make technology faster and more efficient. Industry professionals are looking ahead, and working to allow for inline spectrophotometers, such as the SpectroVision, SpectroView, and SpectroEdge, to become faster, more accurate, and maintenance free. This will remove the need for operators to stop the press, cut samples from the web, and measure the color with a handheld device. The development of inline systems for the world of Flexo has been a large breakthrough and these instruments save printers money and time. On the side of offset printing, there are closed loops systems, such as PressLink to assist press operators.

Advancements in AI-Driven Color Management

ChromaQA with SmartInk allows operators to tone ink with just a few clicks of a button. All the operator has to do is, first, define their specific base ink sets and substrates. This step is a one-time process. Then, AI driven algorithms use this information to correct ink in order to get within a certain Delta E tolerance. This has helped to address skilled labor shortages in the industry and greatly reduces waste and make ready times.

Automation and Real-Time Data in Print Quality Control

The automation of inline spectrophotometers, such as the SpectroVision, has helped press operators have more control over the quality of each job. Devices such as this give real-time feedback about color measurements, and with ChromaQA with SmartInk & InkCheck, the ink density will be adjusted as needed to reduce make ready times and waste.

Find the Right Spectrophotometer for Your Pressroom

When searching for the right spectrophotometer, there are serval factors that you should take into consideration. Functionality, durability, and portability are all important in the press room. Press operators understand that easy to use devices are best. Techkon’s SpectroDens was designed with a screen that is navigated via large buttons, that are easy to see and easy to press.

A touchscreen may not be the best option for press operators, as many times ink will end up on the screen. Durability is another factor to take into consideration. Press rooms are manufacturing facilities, and often times, devices can get knocked over, covered in ink, or dropped. This is bound to happen, which makes it important to choose a device that is able to withstand these conditions. The SpectroDens is held inside of an aluminum case, and has no moving parts, making it very durable. Portability may also be important to some, as they do not want to be tied to a laptop or desktop computer.

The SpectroDens is Wi-Fi capable, meaning that the device can function when physically connected to a computer, or when connected via a Wi-Fi connection. The SpectroDens 4, with Chroma QA, allows for storing and sharing across an entire enterprise. Calibration is no longer time consuming, as team leaders can calibrate and manage an entire fleet of devices at once. There are two different types of calibration. The first is a “small” calibration, which can be done to keep the device consistent during production.

Operators simply have to place the device on the charger, which has a small white tile built in that the device can use to calibrate with. The other type of calibration is much larger and must be done every two years. Operators must send their device to Techkon USA in Danvers, MA.

This is free with the Planned Maintenance Program, and users will be sent a loaner device. In order to maintain accuracy with your device, it is important to take care of it. Make sure to calibrate the spectrophotometer regularly and follow Techkon’s scheduled maintenance guidelines and check for software updates. It is best to keep the device clean, to avoid interference with measurements. For more information about Techkon’s products, visit our website.