An Interview with Dan Remaley from PIA/GATF
Dan Remaley is a senior technical consultant at PIA/GATF speciali
zing in process controls—the measurement of production standards to maintain a level of acceptable tolerances in the print manufacturing process. He helps printers install systems to minimize variation in proofs, plates, and presswork, with the goal of more consistent color and less waste. He is also an industry pioneer in the use of gray balance to maintain consistent color on press, a principle since adopted in new guidelines for commercial lithography.
As a popular seminar speaker, Remaley has shared his message about best practices in color reproduction to hundreds across the country. Since 2003 he has also been the workshop leader of PIA/GATF’s popular workshop, Process Controls Boot Camp.
Prior to joining the consulting team, Remaley was PIA/GATF’s process controls manager. He produced, marketed, and supported customers using the organization’s quality control devices, including plate control targets, press color bars, press test forms, and light indicators.
A 35-year industry veteran, he worked as a color stripper, proofer, platemaker, and press operator, before moving into production management for a color trade house. He joined PIA/GATF in 1996.
We spoke to Remaley at his office at PIA/GATF headquarters.
Question: In your experience, what are the primary reasons that printers have excessive color variation? What’s the tip-off that a particular printer has a serious problem?
Remaley: There are several fundamental reasons for color variation; the majority can be eliminated with good process control. The printing process should be measured at each step. Scanning, proofing, platemaking, and presswork need to be controlled within industry standards and tolerances.
Scans should be in gray balance and color corrected. The proofing system should match the print condition through color management and/or tone reproduction curves.
Each proof should have a measurable, as well as visual, target for conformance to the standard. These targets should contain L*a*b* values, tone scales, and gray balance information.
Every plate should have a target to measure the dot values and exposure. The target should be placed in the plate bend area and will not print. Film-based products need a UGRA scale with microlines—a resolution of 6–8 microlines is considered the correct exposure. This generally equals a 50% film value becoming 54% on the plate. Digitally imaged plates also need a plate control target, although with CTP we are more concerned with the highlight dots 1-2-3-4-5% and the basic curve of the 25-50-75% values.
The printing press has the most variability of all these items. Press sheets should have a color bar that can be used to measure solid ink density, midtone (50%) dot gain (TVI), print contrast (75%), and midtone gray balance (50C/40M/40Y). The pH and conductivity should be measured and checked often, as well as roller stripes, roller durometer, and pressure settings.
The tip-off to a serious problem is what, and how often, do you measure? Do you have separate and distinct plate curves for Y-M-C-K? Color control and management starts in the pressroom and then works backward to the proofing device. I look for checklist sheets, for proofs, plates and press sheets, showing the measurement and variability of each step in the process. You can’t control what you don’t measure.
Question: Between proofing, platemaking, and printing, what stage of the process is in greatest need of better process control?
Remaley: I believe that the major changes that occurred in prepress, namely CTP and digital proofing, dramatically changed the process. Prior to this, we output linear film and made plates and proofs with consistent results. Each product had a wide latitude for exposure and were pretty stable. The pressroom has changed with automation but the basic process has remained the same: ink, water, and paper. We still need process control, but the tools have been the same for years. Contrary to popular belief, linear plates will not allow you to match a print standard or a screen build book.
The two major problems are plates and proofs. The plate curves need to be adjusted so that the press can run the correct solid ink density (SID) numbers and reproduce gray balance throughout the tone scale. Currently press operators move the SID values up or down to create a neutral sheet, but this moves the values away from the standard. It also causes problems with trapping, overprint colors, and ink/water balance.
Digital proofing has replaced the traditional halftone proofing systems. The general problem is that if the press calibration isn’t done correctly then the proof doesn’t match the press sheet. These systems are color-managed by the use of an ECI 2002, or similar target. The press prints this target to the correct standards, and then the L*a*b* measurements are transferred to the proofing device. These targets are compared and adjusted to give a visual match from press to print. Comparing a known value target, on every proof keeps the device from changing color in day-to-day operations.
Question: What best practices do you advise clients to use for controlling color on press?
Remaley: To control color on press we need an instrument that reads density, dot area and/or dot gain. The color bar should include patches of solid, 50%, and a midtone three-color gray. Color bars can be modified to include these patches or we can add a second bar in the trim area. The OK’d sheet should have these values recorded and compared with various pulls throughout the run. As a general rule, densities should be +/-0.10 from the standard, and the dot area should not vary by more than +/-3% from the standard.
Other conditions such as pH, conductivity, and water temperature need to be recorded, as well. When a problem or variation occurs, we can determine the root cause from this data. A simple, yet excellent, method of measuring a press sheet is to measure the midtone gray patch (50C-40M-40Y). When measured as a density, with ALL filter readings showing, you will know how light or dark the images are, and which color is away from gray (Y-M-C). Equal densities mean gray balance!
Question: What industry guidelines or internal standards should companies be running to?
Remaley: There are several industry guidelines. SWOP and GRACoL are for web and sheetfed printing, respectively. These references are in the process of being updated to the new G7 methods. PROP is for packaging printers, and SNAP is for the newspaper printers, each with their own specifications.
Question: You’re a strong advocate of gray component replacement (GCR) for minimizing color changes during a run. To what extent is it being used by commercial printers?
Remaley: The use of GCR helps eliminate variation in four-color printing by removing amounts of Y-M-C and replacing it with black. In Photoshop, medium GCR is the default setting. Have you ever tried to print a four-color photo made to appear as a black & white image? These are nasty to print, the color shifts and casts throughout the pressrun. This image and images that are neutral in color (silver cars) are prime candidates for higher levels of GCR or black replacement. Higher amounts of GCR are needed for web printing because of its natural behavior. Smaller format presses with fewer ink rollers benefit as well, because color shifts are less apparent with images converted to GCR.
With many of the images supplied by the customer, the use of GCR is limited; most customers would not understand the concept. Some RIP manufacturers have GCR built into their product so that screen builds and process images are all converted.
Question: What should a printer expect in terms of their ability to match color during makereadies?
Remaley: The concept of printing to gray balance is critical to matching four-color process and screen builds. If we target gray balance on every job, we have selected the most accurate color to control. When our process control is in place, each job is standardized and measured for these same gray values. Faster makeready, fewer waste sheets, and quicker color OKs are natural outcomes.
Question: Do you recommend different levels of process control based on the type of work being produced?
Remaley: I do not recommend different levels of process control, however you may be able to make the tolerance a bit wider. An example would be process color jobs that are saturated in color, which could have a wider dot gain tolerance than the +/-3% recommended.
If you use and maintain the standard for process control, you will see small variations to the process. Color doesn’t just “change” one day—it migrates slowly, that’s why we don’t catch it! The use of targets, known specifications, and measurable deviation can improve the process continuously.
Question: How do you work with clients and what should they expect in terms of a return on their consulting investment?
Remaley: My approach is to be a trainer as well as consultant. To borrow W. Edwards Deming’s phrase, “I’ll teach your internal champion and I’ll be your external champion.” I generally do a half-day seminar on color reproduction involving everyone at the printing facility. I invite sales, managers, production staff, and owners—everyone—to learn and understand together their role in this process.
I follow each step of the process and recommend areas of improvement and types of measurement. I teach how to use the instruments and what the measurements mean. In scanning or digital capture, we focus on gray measurement and color control. The platemaking area has plate control targets to confirm the plate curve and exposure are correct. If plate curves haven’t been developed, I work with prepress and press to print a test form to the correct numbers and make the necessary tone curve adjustments to print to the standard. I teach the press operators all the attributes of the densitometer and what they represent. Together, we review the press settings, durometer readings, chemistry, pH, and conductivity values.
Once I have a good press sheet (by definition, the correct density, dot gain, and gray balance), we can use the targets to calibrate the proof to the known and validated press condition. The proofs are measured for consistency throughout the day/week/year. This investment in process control procedures and training has resulted in major savings in press makereadies, waste sheets, color consistency, and happier customers everywhere I have visited.
Question: What’s your answer when owners ask “how much will all this process control save me”?
Remaley: My answer is “how much are you losing?” The concept behind process control is that we know the standard values and deviation. All of us in the process are trained and empowered to control our area of the process. This in itself is a major change to our “craft” culture. There is no debating the satisfaction of everyone—production people, sales reps, customers, and owner—when we can actually match a proof!
Dan Remaley can be reached at 412-259-1814 or email@example.com. His next training workshop is scheduled August 6–7, 2007 at PIA/GATF headquarters in suburban Pittsburgh.