By Howie Fenton
If you talk to a group of printers about color management, some say it’s the greatest thing since sliced bread while others say it’s the worst thing since the Rambler. In this, the first article of a two article series on color management systems (CMS) we will discuss the advantages, disadvantages and one hurdle of CMS which is the lack of process control. ,
According to the TrendWatch "Color Management: Another Gray Area," published earlier this year, 63% of respondents report they are using CMS in some capacity. At first glance this seems favorable until you study the data more closely and learn that 50% of the firms consider that "eyeballing" jobs (comparing originals to printed output by “eye”, without measurement tools) is color management..
TrendWatch concludes that adoption of CMS among printers is not wide spread, and is even less abundant for creative professionals and publishers. This is more evidence of the controversies and misunderstandings about CMS. Their conclusions include:
Goals
The goals of CMS are quite elegant in theory. Put simply, your scanner will “see” more accurate color, your monitor will display more accurate color and your proofers and press will print more predictable and reliable color.
At the hands-on level the building blocks of color management are profiles. You create profiles for each device in the process including the scanners/digital cameras, monitors, proofers and presses for specific ink/paper/press conditions. These profiles are created using targets (i.e. IT8.-7) which are measured on color measurement devices known as spectrophotometers or colorimeters.
At a 30,000 foot viewpoint color management is made up of three components:
A simple and elegant idea but complicated and difficult to implement. However the gap between the theoretical and the reality is large, and the obstacles such as the inherent drift in performance of the digital devices, the lack of process control to discover and correct this drift are formidable to overcome. As a result not everyone is successful in the implementation. Some companies get it to work for a week, a month or a year. The result: many walk away from the experience and say “It’s just too hard” or “It’s not reliable enough”.
The Good and Bad
The good news is that the hardware and software have come down in price and are cheaper than ever. The technology is one that has matured over several years and the current version of ColorSync as well as the color management software and hardware are working better then ever.
The bad news is that while the ideas are elegant, the implementation is difficult. There are problems with software packages not working with hardware packages and applications working on the PC and not the Mac. Perhaps the worst problem of all is that all manuals, articles and the training sessions make one large assumption – that you are checking to make sure that nothing changes or that nothing changes in the process.
All it takes is one thing changing in the process and all the blood, sweat and tears you invested in profile creation could be wasted. And perhaps the most frustrating part of the process is that you may assume it's working properly because you spent all this time creating profiles.
According to CMS theory you can use the technology to create profiles for everything from scanners to presses. However, the performance of all the equipment drifts. For example, a 50% dot could be 40% in the morning and 60% in the afternoon. This change in performance is called a drift or variability in performance, because sometimes the performance may go up and other times down.
If we measured the performance of all equipment we would discover that some types of equipment drift a little while others drift a lot. For example, the drift in our scanners and monitors are slow while the drift in our proofers and press can be large. This drift in performance makes the creation and use of profiles more problematic because CMS profiles are only useful when the equipment is working the same way – every hour, every day, every week, every month and every year. The only way to take advantage of CMS is to measure and check the drift, create acceptable and unacceptable tolerances for drift, and recalibrate the device when the drift exceeds the acceptable tolerances.
Process Control
Perlmutter Printing is a division of St. Ives located in Hollywood Florida. Cecil James, the director of digital prepress, learned the hard way the importance of process control in implementing color management. James read everything he could get his hands on, attended the 3-day workshop, went out and bought the software and a hardware and set out to make profiles for various devices.
That’s when he discovered the “the profile chase”. Sometimes the profiles would work, other times they would require adjustment or “tweaking”. The profile might be good for one hour, one day or one week.
James says, “When we first started we ran into some problems, which made the process more difficult. We have two of the best proofers – the Kodak Approval XP4 and Screen TrueRite TCP-1080 – so we started making profiles for them. The profiles would work for a while and then they stopped and we witnessed some unpredictable conversion results."
“It took us a month to discover that these machines and all machines experience drift and how to correct for that drift. We had to measure and control the process everyday, otherwise we were making profiles everyday. Fortunately we discovered a piece of software which made our lives a little easier. It is called Proofcheck and it is made by Southwest Software. It allows us to calculate the upper and lower control limits of the process and tells us when something is wrong.”
What James discovered was the importance of process control, determining what is acceptable and unacceptable drift, and fixing things when the drift falls outside of acceptable limits. The printing process is filled with variables which left uncontrolled, creates inconsistent printing. “Once we discovered the fluctuations in each device we created under and lower control limits. We started with the manufacturers specifications. For example, with the Kodak Approval XP4 the limits where plus or minus .05 for a specific density value.”
The staff at Perlmutter became so proficient at process evaluation that they knew when the devices required maintenance. When the Screen TrueRite TCP-1080 proofer strayed beyond the acceptable tolerance they called Screen. When the technician tested the device they confirmed that the laser diode went out of focus and needed adjustment.
Summary
Everyone agrees that we need a way to make color appear more consistent throughout the process. However if you talk to people who have attempted CMS, some claim success while others report failure. While there are a myriad of possible reasons why some companies succeed while others fail, I believe that color managing the early stages is easier and CMS in the later stages requires a in-depth focus on process control. In the next article in the series we will talk more about the “ugly” side of CMS: late stage process control, printing to specifications, problems with press profiles and an alternative to press profiles which is using dot gain compensation currves with grey balance adjustments
Howard “Howie” Fenton joined NAPL as the senior consultant of digital technology in 2002. Before joining NAPL he was a consultant for GATF and was the editor of a prepress magazine (Pre). As a consultant he audits 35 companies year and as a in-house trainer he performs over 100 seminars a year. He has authored five books on: digital printing, scanning, color management, and emerging digital technologies. Got questions? Email HowieAtPre@aol.com.
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