Concentric Screening
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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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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


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


Registration sensitivity
Registration Sensitivity

150 lpi - AM

20µ Stochastic



Screen Visibility

The smoothest pattern is uniformly spaced


smoothness

Screen Visibility


Concentric screening
Concentric Screening

Conventional Dot

Concentric Dot




Rings limit ink film thickness
Rings Limit Ink Film Thickness

175 lpi “Normal” Dot

175 lpi Concentric Dot





Screen Visibility

FM

Concentric


175 lpi Round

175 lpi Concentric


175 lpi round
175 lpi Round

310 lpi Concentric


Press stability

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%

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Sheets

Press Stability


Best of both worlds
Best of both worlds

• Greater color saturation

• Greater press stability

• Ink savings (10%-35%)

• Higher screen rulings

• More detail than AM

• Smoother than FM


Real world learnings
Real World Learnings

Plate imaging is more critical

Printing is more stable

but … the color is different.


Technical assesment plate imaging
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



Real world learnings today s printer struggle
Real World Learnings: Today’s Printer struggle

Quality Materials Ink Prices

Operational Cost Printed Volume


Benefits quality
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.


Benefits reduce ink consumption
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


Benefits reduce ink consumption1
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 €


Benefits reduce wash intermediates
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


Benefits reduce wash intermediates1
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


Benefits reduce wash intermediates2
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!


Benefits waste reduction
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


Benefits
Benefits

  • Quality

  • Ink Savings

  • Reduce wash intermediates > Waste reduction



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