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Color-Management Aids

(August 2012) posted on Mon Aug 06, 2012

Take a look at the many aids available.


By Tony Quinn

click an image below to view slideshow

Software
When it comes to color-management software, defining the goal expected of the software is extremely important. What overall end result do you expect the software to deliver? There are many color-management software systems available. Some software gives you immediate feedback, allowing you to make a decision. Other software tries to eliminate the decision making process and gives you feedback as in what to do to with a print to make that print conform to a specification or specific color aim.
In a separation workflow, Chromix Curve2 is an example of software that will deliver color-by-color curve data. Curve2 calculates G7 calibration curves.
IDEAlliance defines G7 as: “A method defined by the Print Properties and Colorimetrics Working Group of IDEAlliance. The application of this method enables printers to reproduce a similar visual appearance across printing types and substrates. Today, through the PPC Working Group, experts from across the spectrum of printing disciplines contribute to this important IDEAlliance Methodology. G7 specifies the components of an image that define a similar visual appearance to the human eye.”
Print data is input into Curve2 and the software makes decisions as to what values need to be modified in the separations to achieve gray balance. In order to get the color data into Curve2, you must print a P2P target (Figure 3). Using a spectrophotometer, the P2P color data is captured and saved as a text (.txt) file. Once you have the data, Curve2 will give you feed back as to how to modify the separations (Figure 4).
IDEAlliance certifies systems to ensure the system meets industry tolerances for excellence and are capable of calibrating a printing device to meet established tolerances for G7 grayscale definition.
Currently three systems are certified by IDEAlliance, Fujifilm Taskero Universe ColorPath Sync, Heidelberg Prinect Color Toolbox, and Chromix/HutchColor Curve2.
Print analysis, trending, and capturing okayed print data are very important. When things are working perfectly, capture the print data. Analyze the print and store the data for future reference. If you have data to fall back on, when things fall apart (not wishing bad luck on anyone, just a realist), you will have data to help you evaluate the fail point in production.
If a client were to ask, “How would you guarantee the color consistency of the print, after the color has been okayed?” How would you answer? Answering the client’s question would be very easy if you had the ability to capture print data during a run and then compare the run data to the OK sheet.
Nazdar Consulting Services (NCS) developed software that monitors the print process. Data Capture System (DCS). DCS is a system that captures print data from a color bar (Figure 5). Once a print job has been approved, successive press sheets can be read into the DCS system. It evaluates the current printed color data to the color data previously entered. Figure 6 shows DCS density comparison between two data sets. The dotted lines in the graph represent the original print data, while the colored lines represent the current print data. Other examples of print-data-analysis software include SpotOn!, Alwan Print Standardizer, Measure Color, and ColorMetrix
Having the ability to evaluate an ICC profile can really make or break a digital department. If you start from scratch and create a media configuration—individual ink-channel limits, total ink limits, linearization curve and ICC profile—the final step before testing the configuration should be evaluation of the ICC. The custom ICC profile created during the media configuration process is a snap shot or picture of how a specific printer, substrate, resolution etc. work together. Using software to evaluate the ICC gives you immediate feed back on how well the media configuration process worked.
ColorThink Pro from Chromix has tons of functionality. One of the easiest checks using this software is to compare one ICC profile to another. Since all CMYK ICC profiles have the same shape, you can compare the ICC profile created during the media configuration process to an industry standard ICC profile. If the profile has the same basic shape as the target ICC, not necessarily the same gamut, the media configuration was successful. Many times the custom ICC profile will have a smaller or bigger gamut than the target ICC. This is due to differences in materials, printers etc. Once again, look for the shape of the ICC to be similar to the industry standard ICC.
Figure 7 shows a ColorThink Pro evaluation of two ICC profiles. The goal with this media configuration was gray balance so GRACoL2006_Coated1v2.icc profile was used as the target (GRACoL2006_Coated1v2.icc outlined in red, Roland profile multi-colored). The printer profile was created from a Roland custom media configuration. The Roland ICC profile is larger than the target ICC.
Knowing the custom printer ICC is larger than the target ICC immediately identifies the media configuration should be able to achieve the majority of the colors in the target color space. Also, the shape of the custom ICC profile is close to the same shape as the target ICC. By no means is the shape exactly, perfectly the same, but it’s in the ballpark. When a custom ICC profile has a dramatically different shape compared to the target, you know you have a problem. In certain instances, the ICC patch data may be corrupt or wrong. If the data is read in backwards or the wrong row is read into the collection software, this will generate bad data and corrupt the shape of the ICC.
Instruments, spectrophotometers, densitometers, data-collection software, curve software, and ICC-profile-analysis software all have one thing in common. These are the aids or tools used to achieve the most accurate color with the least amount of headaches. Have you ever tried to play darts with your eyes closed? If your overall approach to color management, regardless of the type of printing you are doing is visual only, or eyes closed, get ready for longer make ready times, more wasted material, increased labor costs, and customer rejections, just to name a few of the resulting problems.
Having the right color-management aids or tools in combination with a defined color management game plan should help improve your profitability and throughput. With so many color management options available, which way should one turn? Define the goal. Once the goal is defined, finding the right color-management aid or tool is not that complicated.
I started this discussion by giving some examples of color-management goals. Before you decide on a new software package or instrument, take a look at what you’re trying to achieve. Ask the printers what would help them get a job through the facility with fewer headaches or what the most difficult part of their job is. One would be surprised how often the person running the equipment can tell you where the holes in production live.
I said I was a realist, so once again: There is a big difference between productive, problem solving compared to flat out complaining. Most people try to do the best job they can do, so if you ask, you should get good honest feedback most of the time.
Color-management aids or tools will open your eyes to the color in your facility. Just make certain to define the goal, and then pick the aid or tool for the job. Don’t get stuck with a pair of needle nose pliers when the job calls for a pipe wrench.

Tony Quinn is a Nazdar Consulting Services (NCS) consultant, a certified G7 Expert, and a Color Management Professional (CMP) Master Trainer. He started his career in graphic arts after nine years in the US Air Force working on F-16 fighters. He has 20 years of experience in the graphic-arts industry and has been a lead consultant on more than 50 screen, digital, and offset G7 qualifications. He has taught color control and prepress at the SPTF Process Color Workshop and in the Nazdar Masterprint seminars. He is one of the lead trainers for the SGIA Color Management Boot Camp.

 

 

 


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