SpotOn Color Software

Color Management Verification

Tricks to Matching Multiple Printers

by 2 Comments

Calibration of a single printing device is not always the easiest task, and matching multiple printers to one another is an even bigger challenge.

Three Key Things To Matching Multiple Printers

One question that has come up frequently is “what is the best way to profile multiple devices of the same model?” If you are trying to achieve a close visual match between printing devices, there are three key things to consider:

1) Printer gamuts have to be pretty close between devices. This has a lot to do with substrate texture and ink texture.

2) It is necessary to evaluate more than just the worst ∆E value. You need to know how all the patches in a control strip compare in ∆E, not just the worst or the average. When choosing a control strip,the more patches, the better, as long as the chart doesn’t become too large for practical daily use. The more patches under 1 ∆E, the more likely the printing is visually close.

3) You can’t compare to an industry reference, like GRACoL, when visually comparing devices. You have to compare one device as the reference to the other because that’s what you’re looking at in the viewing area. You can’t see GRACoL, as there is no perfect GRACoL proof. But you certainly can see the difference between printer A and printer B. So make printer A the reference when comparing those two devices. Hopefully with grouping tests you can compare multiple devices to one device.

Calibrating The Device

Tight calibration of the device and the ability to truly recalibrate back to the same known state is key.

From my experience, the automated “recalibration” process does not always work well in the field. Some RIPs are better than others. The bottom line is for true recalibration to work it has to be a two-part process.

First, you have to achieve the same solid ink value that was in the original calibration

Second, you have to then create the same curve along the values between 0% and 100%.

Most RIPs do the latter, but few actually do the former during the automated recalibration process. If you can’t fully recalibrate the printer, the original profile is eventually going to be too far off the mark.

grey_img_blog

A Single Profile Doesn’t Always Work For Multiple Devices

Also consider that very rarely do two of the same devices that are the same age print the same color out of the box.

I’ve proven this many times when evaluating color output data during calibration sessions. There is no way to successfully use a single profile for multiple devices that aren’t even close to a tight visual match.

My advice is to target the same source reference space (GRACoL as an example) for each device. Then calibrate and profile each device as carefully as possible to achieve as tight a match as the RIP can provide.

When finished, you can compare how close each device is to one another by printing a test chart and comparing the measured results. RIPs that have iterative optimization have a much better chance of achieving a tight calibration between multiple devices.

Run Comparison Tests For Matching Multiple Printers

You certainly can and should run comparison tests between all your devices (ideally on a single substrate all devices can print on) to identify which devices are the closest to one another and group them accordingly.

The point here is to get to know each and every device (it’s gamut, how consistently it prints, etc.). Maybe you get lucky and find several devices that actually are close enough to calibrate using a single profile. Only after going through the process of calibration and evaluating the results can you truly know the color capability of each device.

I have installed many pairs of Epson aqueous printers and have never found two that calibrate the same or profile the same, however, following the process described above will get them to the closest possible visual match.

SpotOn Verify is the ideal tool for comparing the calibration results of each printing device. SpotOn Analyze is the ideal tool for setting ink limits and examining the color differences between each printing device. Try them for yourself!

Real User Stories: Global Color Control

by Leave a Comment

Note: Joe Pasky wrote this post.

P1160562

Last year, I worked with a well-established company in Pennsylvania that specializes in ‘museum quality’ art and photography books. They were considering several titles for their first Asia production attempt.

But the company had a concern that the quality that their reputation was built upon would not be upheld by the new contract facility.

Additionally, they wanted to implement a color control and monitoring process at their U.S. factory.

Color Control Between Facilities

They wanted to bring the proofing of both facilities to within 90%+ of GRACoL 2013 target values.

We matched the printing color to these accurate proofs. We wanted to ensure their customers continued to receive the same high quality products. The company would be able to efficiently control color in two facilities nearly 8,000 miles apart.

Bringing In The Color Experts

First, we realized this was a job for color experts. So we asked Bruce Bayne from Alder Technologies to spend several days in the Pennsylvania facility and calibrate their new Epson SC9900 proofer. He also installed SpotOn Color Verify to bring their quality monitoring and QC assurance procedures to the next level.

Moving forward, they would use Verify to control the print process by monitoring and tracking the consistency and accuracy of proofs made in the US and abroad.

Next, the Cathay America team used SpotOn Color Verify to calibrate and monitor the Epson proofers at the printer’s new facility in Shenzhen, China. Verify’s Visual Match feature guided our calibration work and helped ensure proofers on two continents would match accurately.

Finally, we calibrated the U.S. based press. The Cathay America team calibrated the presses in China. Both were able to achieve GRACoL2013/CGATS/CRPC6 target values. This was the last step to bring all of the proofing and production devices into alignment.

Global Monitoring

We implemented a global monitoring and QC assurance system that would allow our customer to achieve the same high quality press work over time.

We impressed our customer by the quality of their first prints from Asia. The U.S. client/printer and the photographer whose work we reproduced were thrilled with the quality of the images in this very impressive book. Most importantly, our U.S. client was confident that he could print his high quality museum editions at our China facility.

Moving forward, many more titles are produced with excellent color. This was possible because of our process control program enabled by SpotOn Verify.

The details of our method are below.

Click Here to try SpotOn Color Verify

P1160560

Using SpotOn Color Verify to monitor and control presswork.

The Methodology of Color Control

The printer had 10 fairly new, well-maintained Komori presses, each with an Intellitrax scanning spectro. But the intellitrax software was several generations old and didn’t report anything more that solid ink densities (SID).

This limited color data was simply not enough information to tightly monitor production printing. We could not achieve the accurate and consistent color control that we required. The printed images were quite well known. Our client needed assurance that the original images would reproduce accurately.

Finally, we decided to print on a slightly larger press sheet so that we could add a second set of colors bars to the sheet.

We placed one control strip in each of the four alleys of the book pages below the Intellitrax scanner’s control strip. These 18-patch, custom color control strips are designed to be scanned by an i1Pro2. After scanning, we sent the measurement data to SpotOn Color Verify.

DSCF0437

Press proofing key images before the production run. Notice the SpotOn Color Version 2 color control strips that run vertically. We could use SpotOn Color Analyze to measure and display comprehensive printing data.

When A Shift Happens In Color Control

If the press has shifted, the ink can be leveled accurately by scanning the press color bar with X-Rite’s Intellitrax system. Then, you can scan the custom color control strips in each of the four alleys. We used the i1Pro2 and SpotOn Verify to monitor compliance with CGATS21/CRPC6 target values.

Finally, we used Verify to display the data from each scan for the operator to evaluate compliance. If the press is out of compliance, the operator can take further corrective action to bring the press back into tolerance.

my bar

You can achieve great color and you can maintain it efficiently over time. You need the desire to control the process.

–  Joseph J. Pasky, Shenzhen

Test Form that Bob Signed

Patches: C, C50, M, M50, Y, Y50, Red, Green, Blue, 3/c Black, 100k, 25k, 25cmy, 50k, 50cmy, 75k, 75cmy, paper white

Try SpotOn Color Verify

Which Chart Is Best For Color Process Control?

by Leave a Comment

Recently, a color process control manager wanted to know if there is a more comprehensive chart available for daily digital color evaluations than an 12647-7 proofing wedge.

He pointed out the IT8.7-4 has too many patches and the P2P51 has too many gray finder patches. Reiterating a thought we’ve all had many times, he asked: “Am I overthinking the value of additional patches?”

Patch Count On Color Process Control Charts

There is a tradeoff between patch count and how effective a chart is at gathering quality control information.

There are two extremes: too many patches and too few patches.

Too many patches on a noisy (grainy, low screen ruling, etc.) printing device can cause unwanted noise in the measurement data. If you have too few patches, you are not sampling enough colors to accurately model how the device is printing.

I dissected the TC3.5 patch set and found it to be lacking in the 3 color grays. There are not many patches and none are G7 compliant gray patches. In my opinion, this eliminates the TC3.5 for any G7 evaluation.

In fact, most of the currently available charts are not very good in the gray areas, especially if you are trying to evaluate G7 compliance. IDEAlliance built the TC1617 to address this lack of G7 gray patches in the IT8.7-4. But even this chart has too many patches for day-to-day evaluations.

A Chart That Is A Good Compromise

Building the 3-row 2013 12647-7 chart was a very good compromise between patch count and patch value.

It has a decent number of patches to effectively evaluate print consistency, which includes G7 compliant gray patches, the typical array of CMYKRGB tone ramps, pastel patches, saturated patches and a good assortment of dirty patches.

These dirty patches were purposely built with CMY values and then with 100% gray component replacement (GCR) values excluding the 3rd color and replacing it with K. Many separations, especially those done with ink reduction products, are made with GCR these days.

It’s hard to beat what’s in that 3-row, 84-patch control strip.

wedge_image
The 3 Row Control Strip with key patches highlighted.

While considering charts and patch values, it’s almost more important to note the metrics and tolerances we place on these patches for conformance to specifications.

If you look at the metrics we currently use for pass/fail, they are very CMYK printing press-centric.

Commercial print has been the forefront of most industry standard and best practice development. Therefore, much of the data gathering and evaluation is based on printing devices where C, M, Y, and K ink thicknesses are controllable by the operator.

Most metrics tied to effective control of those ink thicknesses are largely irrelevant to the digital world.

We should be asking: “What are we passing and failing?”

For the G7 Colorspace metrics (currently the most stringent), we are evaluating:

  • Substrate – Paper color is good to evaluate
  • Solid CMYK – Very useful to press operators, but not much of a typical image or job is just solid C, M, Y, or K. This makes these patches poor for evaluating digital print consistency, especially visual consistency.
  • Solid RGB overprints – In my opinion, this is more important than Solid CMYK, as overprinted colors are what we see when we look at printed material. Still, these are only the solids, no tints.
  • CMY gray balance and tone – This is very important in controlling and evaluating print consistency, although it’s more important in print processes that lay down individual CMYK inks like offset.
  • All the other patches (pastels, saturated, dirty colors, skintones, CMYKRGB tints) are all lumped into a single metric called ‘All’ and then given a whopping average ∆E of 1.5 or 2.0 and a worst patch ∆E of 5.0 (95th percentile). That’s huge! A virtual barn door to let almost anything outside of grays and CMYKRGB solids pass.

These are not very visually oriented metrics and tolerances. So the big question to ask is what are you evaluating with your chart, or more importantly, what metrics and tolerances are you using to evaluate your chart?

For G7 you could just use a P2P and eliminate the gray finder patches (columns 6-12) because the metrics are really only focused on CMYKRGB solids and the gray patches.

The Bottom Line Of Color Process Control

If we are looking for print consistency, we need to look at establishing new metrics that truly help us determine how visually consistent a print is.

After a great deal of research, I believe a cumulative relative frequency model (CRF) that evaluates all colors in a chart works best. In a CRF model, each patch is relevant to visual consistency and counted within the evaluation.

I have found the 3-row control strip does an excellent job of evaluating visual print consistency when using CRF. I’ve also performed the experiment in live production many times. I have continued to get feedback from users who say using CRF. The 3-row control strip is the best method they’ve found to evaluate visual consistency.

If you would like to see the true power of CRF and real world metrics, try SpotOn Color Verify. The trial is free, and our team will help you start.

Real User Stories: Process Control for Seagate

by Leave a Comment

pasky_image_trio

Long-time SpotOn Color user Joe Pasky offers insight into the value of process control.

Eight years ago, Seagate Technologies asked me to help them with process control to qualify for G7 certification. They had six printing plants in China and Thailand which produced retail cartons for disk-drives.

They had difficulty with variations in the color appearance of similar product images that were printed at different factories. However, a single color house in the U.S. created the files and proofs for these images. But they had several runs of cartons rejected. When they reprinted those runs, it caused delays in the product release schedules and extra costs.

Press Checks and Press Sheets in Process Control

When doing press checks on new products, they asked the printer to produce a press sheet that matched the supplied proofs as closely as possible. They approved this best match. It became the master reference sheet for printing all subsequent SKUs that used those particular brand colors and product images.

 

The problem with this approach was that the printed product images approved at one factory were sometimes different from identical product images produced at other Seagate printers.

 

Finally, we began to certify each of the printers and train them to “print to the numbers.” The color differences between the master reference sheets at the multiple printing plants was greatly reduced.

Color Mismatch With Cartons

When traveling to the States a few months later, I visited a Best Buy store. I took particular notice of the display of Seagate disk drives, which were cartons that I had approved several months earlier.


Looking at the same and similar cartons side-by-side, I noticed an obvious variation in color and balance. I took photos of the UPC codes to identify the printer and began an investigation.

 

As it turned out, the operators were not being vigilant in monitoring the color during the press run.

Taking Back Control of Process Control

First, we implemented a new sampling procedure. We pulled and time-stamped a percentage of sheets from the press run. Then, we measured them by the quality control department. We sent reports from each production run to the Seagate China office for review.


However, this procedure required extra effort and attention from the press operators and supervisors. After several months of monitoring, the printing consistency improved and variation reduced.

 

Second, we wanted to sample the individual cartons after creation. But once the carton was die cut from the press sheet, there was nothing to measure.


In other words, the press color bars were gone. To solve this problem, we built a 7-mm, 14-patch control strip hidden in the glue flap. We placed another control strip placed in the tuck-flap of the box.


The patches on this strip included two brand-color patches, paper-white, CMYK, 3-color black, and the G7 tone value targets: 25k, 50k and 75k and 3-color, ¼-tone, midtone and ¾-tone tints.

Verification Software To The Rescue

First, we used SpotOn Color Verify software to check digital proofs. We realized that we could also use Verify to scan the printed control strips.


We took samples of finished boxes from the production runs and used Verify to quickly measure and record the color data. SpotOn Color’s reporting function helped us build a quality report and history for each of the production runs.

 

Moreover, the press operators also began using Verify during make-ready to measure the control patches. We wanted to be sure that they were hitting their G7 target values and assure that they would pass the QC department’s ‘pass/fail’ criterion.


It was an excellent tool that was very easy to use in production. We no longer use proofs as a color reference; we’re printing 100% ‘to the numbers’.

Process Control Works

As a result, Seagate was quite pleased with the results. For the past six years, each of the factories have been using Verify to monitor color on press and in the quality control department.

Therefore, cartons from each of the factories and the images for each SKU were an excellent match to each other. All the printing plants were printing product images that were accurate and consistent from SKU to SKU and run-to-run. Color variation between boxes produced at multiple factories was practically eliminated.

 

Using SpotOn Color Verify to measure these simple hidden color control strips was successful. Therefore, we incorporated G7 data points that made it possible to monitor and improve packaging color reproduction across multiple facilities. Any brand hoping to improve color consistency of printed packaging could use this approach to improve quality and color fidelity.

Joseph J. Pasky

Cathay America

Shenzhen, China

jpasky@gmail.com

Analyze Is Here!

by Leave a Comment

Image of SSMA_mailchimp_header_bullseye

Exciting news!

Today, we’re announcing the launch of Analyze. It is the ultimate weapon for print industry professionals who are serious about printing great color.

Simply eyeballing color doesn’t cut it anymore. In fact, it’s a recipe for disaster. It causes lost time, lost customers, and lost profits. Pros know you can’t manage what you don’t measure. Therefore, they collect data and use it to maximize color control.

As a result, G7 experts and in-house color gurus use Analyze to map device behavior, aid G7 calibration, and outperform the competition every day.

Analyze is a powerful addition to print management software that further increases the efficiency of the printing process. It presents detailed color data in a simple visual interface.

In addition, Analyze helps printers improve consistency and increase the accuracy of color calibration for all types of printing devices. It puts process control in users’ hands, helping deliver quicker turn times, reduced ink and paper waste, and improved profits.

In today’s competitive print industry, efficiency and accuracy are the keys to success. Subsequently, Analyze helps users streamline the G7® certification process and maximize the results over time. We are thrilled to announce this significant step forward for the color industry. Meanwhile, we are ready to help you integrate it into your workflow.

Data drives profitable production in any industry; and printers can use it to take control of color and the bottom line.

Most importantly, Analyze is a powerful tool that allows you to streamline G7® calibrations, capture detailed performance data, and anticipate issues before they start. The software enables you to implement process control, make continual performance improvements, and maximize profits. Analyze stops the guessing game by bringing color into the digital age.

Take the wheel. Get SpotOn Color Analyze.

Connect With Us

About Us

GetSpotOnColor.com distributes and supports SpotOn software products on behalf of Hal4D Consulting, LLC

Contact Information

help@getspotoncolor.com
866-91-COLOR
(866-912-6567)