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ColorMetrix User Group 2004 Keynote presentation by Howard Nelson Ed.D ColorMetrix 4th Annual User Group Meeting August 8-10, 2004 Las Vegas, Nevada
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Print Measurement as Historical Eras Decades in which projects were initiated (and perhaps continue to evolve) Provides us with an overview of where we came from, so we might be able to predict where technology will take us next
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50 Years of Print Quality Verification Measurement of printing through print characteristics Print consistency control Print quality control
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LTF Began researching lithographic technology during WW II for the US War Department Began to research and consult for private industry after the War Became GATF in the 1960’s
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Historically Speaking The 1950’s were the research era Introduction of the scientific approach to problem-solving LTF began to publish their findings in the “popular trade-press” First densitometers became available
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Historically… 1960’s were the developmental era Web offset printing grabbed the market- share for most impressions Densitometers became widely used GATF pioneered print characteristic identification and calculation
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Historically 1970’s were the standardization era SNAP - 1970 - 1972 SWOP - 1976 - 1980 Color proofing systems introduced Print measurement investigates ink/paper/chemistry relationships
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Historically 1980’s were a consolidation era CEPS systems improve halftone control Color proofing systems improved First Spectrophotometers available Print measurement data feeds back to improve prepress accuracy
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Historically 1990’s were the era of verification No-proof editorial Spectrophotometers become generally available ColorMetrix Technology LLC Press “Fingerprinting” for process control
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Press Fingerprinting Five rules of Press Fingerprinting Simulate production Choose a test form Run the form Measure the sheets and collect data Feedback to prepress A step beyond??
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Print Control Measurements Solid Ink Density Dot Area Gain (at the 50% dot value) Print Contrast % Trap (for Wet Ink Trap) 3/C Neutral Gray Balance Hue Error and Grayness Error
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Solid Ink Density Makeready aimpoint for color approval Print consistency target Basis reading for other calculations One of the main image contrast indicators
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Dot Area Gain Image contrast indicator
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Print Contrast How well the press/ink/paper combination is able to render shadow detail by differentiating between shadow area tone values
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Wet Ink Trap Control of secondary (RGB) colors
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Verification Fingerprinting Monitoring “Sheet Contrast” At a given Solid Ink Coverage, print contrast characteristics shouldn’t vary C=1.30, M=1.40, Y=1.05, K=1.60 DG=20%, PC=40%, Trap Fingerprinting to verify press components are functional
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Press Component Life Like aircraft component parts, press parts are rated for useful life Plates & blankets by # of impressions Rollers by # of operating hours Even cylinder bearers are rated TBOoR components
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Verification Fingerprinting Run test form under “Press New” conditions Discover and monitor TBOoR for press parts Re-run test form to verify need for replacement Watch sheet contrast for clues
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Scanable Press Test Form The scanable press test form
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Scanable Form Components Two-tier standard color bar Scanable color bar
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Scanable Form Components Scanable ICC color profile
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Scanable Form Components Scanable Tone Ramps
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Scanable Form Components Scanable Gray Balance Ramps
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Scanable Form Components Scanable Total Ink Coverage Ramps
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ColorMetrix Collects and displays graphic data Displays Run with VOC tolerances Process Trending Color hexagon Press fingerprinting Data sharing with other programs
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Historically Speaking 2000 - 2010 may be the era of SPC Use of statistics to identify problems Use of statistics to monitor runs Using statistics to predict outcomes
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Six Sigma Data Analysis Specifies the amount of variation experienced compared to the specs Greater process predictability Lowers costs by minimizing waste and rework Isolates special cause variation from common cause variation
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Descriptive Statistics Mean The average of the data as collected Standard Deviation The value of one sigma
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Run Chart Note the value of each individual point Observe trends during the run Runs up and down vs expected runs Observe the P-Value P-Value for Clustering, P <.05 = Special Cause P-Value for Mixtures, P >.95 = Special Cause
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I-MR Chart Individual Value of each data point of the run Mean, UNPL, LNPL Moving Range of the differences in value during the run Average range, UNPL, LNPL
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Process Capability Analysis The Cp index Ratio of the spec limits to the width of the process Cp = 2 means the process is stable Cp ≤ 1 means the process is unstable The Cpk index Ratio of the process width to the spec width including centering of the spec on the process Cpk > 1 means the process is capable of meeting spec Cpk = 1 or less means the process is incapable of meeting spec
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Differences in Process Capability
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Some Words of Thanks Colormetrix Technologies LLC Jim Raffel, Mike Litcher, Mike Woods E. I. DuPont de Nemours GATF / PIA and Gretag-MacBeth Flint Ink Corp. Jeff Gilbert, Craig Stone
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