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Concentric Screening

Concentric Screening. Commonly used Screening. Amplitude Modulated screening. Modulates the screen area by changing the size of halftone dots. To get darker colors, the process uses larger dots — a larger amplitude

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Concentric Screening

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  1. Concentric Screening

  2. Commonly used Screening

  3. Amplitude Modulated screening • Modulates the screen area by changing the size of halftone dots. To get darker colors, the process uses larger dots — a larger amplitude • This has been the typical method for creating halftones and process screens for the last 100 years or more. • Acceptable dot gain • Smoothness

  4. Frequency Modulated screening • Modulates the screen area by changing the number of randomly distributed dots of the same size that appear in a given area. • Can solve registration issues • Has fine Detail • Better press stability • Good color saturation • Ink Savings • More stringent process control • Grainy midtones and vignettes rather than a smooth gradation in tone. • Buildup of ink or paper residue on the printing press blanket

  5. Registration Sensitivity 150 lpi - AM 20µ Stochastic

  6. Finer Detail

  7. Screen Visibility The smoothest pattern is uniformly spaced

  8. smoothness Screen Visibility

  9. Concentric Screening Conventional Dot Concentric Dot

  10. AM vs Concentric

  11. FM vs Concentric

  12. Rings Limit Ink Film Thickness 175 lpi “Normal” Dot 175 lpi Concentric Dot

  13. Mass tone effect

  14. Mass tone effect

  15. Color Saturation

  16. Screen Visibility FM Concentric

  17. 175 lpi Round 175 lpi Concentric

  18. 175 lpi Round 310 lpi Concentric

  19. 90,00% 80,00% 70,00% AM 25% 60,00% Concentric 25% AM 50% 50,00% Concentric 50% Percentage in print 40,00% AM 75% 30,00% Concentric 75% 20,00% 10,00% 0,00% vel1 vel2 vel3 vel4 vel5 vel6 vel7 vel8 vel9 Sheets Press Stability

  20. Best of both worlds • Greater color saturation • Greater press stability • Ink savings (10%-35%) • Higher screen rulings • More detail than AM • Smoother than FM

  21. Real World Learnings Plate imaging is more critical Printing is more stable but … the color is different.

  22. Technical Assesment : Plate Imaging 1. Use premium plate material 2. Optimize processing 3. Optimize laser focus 4. Optimize laser intensity 5. Optimize beam alignment 6. Calibrate your plate

  23. Technical Assesment : Plate Imaging checkerboard

  24. Real World Learnings: Today’s Printer struggle Quality Materials Ink Prices Operational Cost Printed Volume

  25. Benefits: Quality • Quality is nr 1 pain, due to decreasing quality paper and ink. Daily fight to keep the printing process under control. • Customer quote: the best thing that I like about Concentric is the fact that my customers don’t see anything related to screening, but notice an improved quality.

  26. Benefits: Reduce ink consumption • Cost reduction: ink prices increased 30% in 2008, ink represents up to 17% cost of printed job. • Less ink means less wash intermediates: time + cost savings & waste reduction

  27. Benefits: Reduce ink consumption 1 Manroland LithoMan 48 pag presses operating in 3-4 shifts, 50-60.0000 copies/hour • Ink consumption: 500.000 kg • Cost: @ 3 € per kg 1.500.000 € • Savings 15% 220.000 €

  28. Benefits: Reduce wash intermediates Why wash? Blanket cylinder gets polluted by f.i. paper particles Paper particles are picked from the paper by ink Less ink = less particles Less particles = reduction of wash intermediates After every 50.000 copies or approximately 1 hour of printing there is a wash intermediate that takes a few seconds... No big deal? Washing cycle: The machine reduces speed to 30.000 copies an hour The press stops printing, the paper continues its travel trough the press into the waste container... The whole wash sequence takes 2 minutes 1.000 signatures are thrown away, no matter what size the press, every hour, day in, day out

  29. Benefits: Reduce wash intermediates Feedback from reference site : Heatset Presses • 2 x 64pp presses. • 6 x 48pp presses. • 1 x 16pp press. Coldset Presses • 2 x 64pp presses. Quote: “We have decreased our wash intermediates, we print 60.000 copies instead of 50.000 copies”. In practice: 4 wash intermediates less per day

  30. Benefits: Reduce wash intermediates 2 minutes at 30.000 signatures/hour = 1000 signatures 1 signature = 1.62 m2 1000 signatures = 1620 m2 Paper weight: 60 gr/m2 Paper waste in 2 minutes = 97.2 kg.....every hour!

  31. Benefits: Waste reduction Without Concentric Screening: 24 wash intermediates x 97.2 kg = 2330 kg paper waste per day With Concentric Screening: 20 wash intermediates x 97.2 kg = 1944 kg paper waste per day 2330 - 1944 = 356 kg per day WASTE: yearly (200 x 356 kg) = 71.200 kg

  32. Benefits • Quality • Ink Savings • Reduce wash intermediates > Waste reduction

  33. Think inside the dot.

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