Long-time SpotOn! user and product dealer Joe Pasky at Cathay America offers insight into the value of process control…
EIGHT years ago, I was asked by Seagate Technologies (California) to help them G7 qualify the 6 printing plants that they used in China and Thailand which produced retail cartons for disk-drives. They were having difficulty with variations in the color appearance of similar product images that were printed at different factories, even though the files and proofs for these images were created by a single color-house in the States. Several runs of cartons were rejected and had to be reprinted; this caused delays in the product release schedules and extra costs.
The original strategy for press checks on new products was to ask the printer to produce a press sheet at make-ready that matched the supplied proofs as closely as possible. This best match was approved and 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.
As we began to G7 Qualify 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.
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; cartons that I had approved several months earlier. Looking at the same and similar cartons side-by-side, I was disappointed to see a noticeable 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. We implemented a new sampling procedure where a percentage of sheets from the press run were pulled and time-stamped. These were measured by the QC department and reports from each production run were sent to the Seagate China office for review. This procedure required extra effort and attention from the press operators and supervisors, but after several months of monitoring, the printing consistency was improved and variation reduced.
Monitoring the press sheets was effective, but we also wanted to sample the individual cartons after they were formed. But once the carton was die cut from the press sheet there was nothing to measure. The press colorbars were gone. To solve this problem, we built a 7-mm, 14-patch control strip that was hidden in the glue flap and 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.
We had the experience of using SpotOn! Verify software to check digital proofs. We realized that we could also use SpotOn! Verify to scan the printed control strips. We took samples of finished boxes from the production runs and used SpotOn! Verify to quickly measure and record the color data. SpotOn!’s reporting function helped us build a quality report and history for each of the production runs.
The press operators also began using SpotOn! Verify during make-ready to measure the control patches 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’.
Seagate was quite pleased with the results. For the past 6-years, each of the factories have been using SpotOn! Verify to monitor color on press and in the QC department, 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! Verify to measure these simple hidden color control strips that incorporate G7 data points has made it possible to monitor and improve packaging color reproduction of finished folding cartons across multiple production facilities. Any brand hoping to improve color consistency of printed packaging across a global supply chain could use this approach to improve quality and color fidelity.
Joseph J. Pasky