ssfc
04-07-2012, 08:46 AM
<br>
Characteristics of AM and FM ScreeningThe digital revolution has brought a sea change to the prepress world, but the nature of the final printed product has hardly changed at all. Most color print matter with strong visual elements, such as brochures, pamphlets and magazines, is still printed using the same conventional 175 lpi Amplitude Modulation (AM) screening methods that were used before the digital revolution.Conventional AM screening reproduces light and darkness by varying the size of halftone dots. It is currently the screening method used most often in printing, because the pitch and angle of the dots are fixed, and the method achieves consistent tonal reproduction.Nevertheless, AM screening has drawbacks. Because the halftone dots are evenly spaced and at angles, AM screening is prone to moiré resulting from factors such as plate misalignment and interference patterns between screen angles and images. Other typical problems include jaggedness and segmenting of fine lines and tone jumping in gradation areas. These kinds of problems are particularly troublesome because they are generally not detectable prior to printing. These problems have also hindered the transition to fully digital workflows, the adoption of computer-to-plate (CTP), and the streamlining of the color proofing process. Efficiency-boosting measures such as direct digital color proofing, or using a color printer for proofing, remain problematic because of the risk of overlooking problems such as moiré.Trying to achieve higher print quality by using higher frequency AM screen rulings also has drawbacks, since printing with high-frequency screening requires much stricter print management conditions. This is why only a small minority of printers use high-frequency screens of 300 lpi or higher. And despite the spread of powerful graphics software that makes it simple to generate high-resolution data, the most common screening method in use, 175 lpi AM screening, leaves the graphic arts industry largely unable to get the most out of its detailed graphics and images.Frequency Modulation (FM) screening spent some time in the limelight as an alternative to conventional AM screening. FM screening places microdots of equal size randomly, varying their density to reproduce lightness and darkness. Not only does this approach eliminate the moiré and broken lines associated with AM screening, it also supports higher resolution printing. Unfortunately, FM screening demands a rigorous print production environment, which translates into higher printing costs. Also, in comparison to AM screening, with FM screening it is more difficult to print midtones and shadow areas consistently, and the midtones and highlights tend to appear grainy. Despite its other advantages over AM screening, FM screening’s own drawbacks have kept it from being more widely implemented.Spekta: Combining the strengths of AM and FM screeningDainippon Screen has taken the best qualities of both AM and FM screening, and melded them together in an innovative hybrid screening product, Spekta. Spekta overcomes the weaknesses of both FM and AM screening, while delivering their key strengths, to make highly-detailed, high-quality printing a reality using ordinary equipment. It uses AM-like dots or FM-like dots depending on the color density of each area being output. By doing so, it achieves the following remarkable characteristics:1. With the standard 2,400 dpi resolution that is typically used to output 175 lpi AM screens, Spekta achieves a level of detail comparable to high-frequency line screens of 300 lpi or higher. Moreover, it produces no jagged or broken lines.2. Spekta screening does not generate moiré because it creates no screen angles.3. It can be printed under standard printing conditions and there is no need to retrain operators.Varying the screening as required for each density rangeIn the 1–10% highlights and the 90–99% shadows, Spekta uses FM screening’s fixed dot size and reproduces tone by varying the density of uniform dots. In the 10–90% midtones, it varies the size of the round dots just as AM screening does. The placement of all these dots is random, as in FM Screening, however, which means there are no screen angles to contend with. As a result, Spekta avoids the moiré resulting from factors such as plate misalignment and interference patterns that plague conventional AM screening. Spekta overcomes the difficulty of printing FM screens by setting the size of the smallest dot slightly larger than in FM screens. It also minimizes tone jumping through advanced methods that control the positioning and joining of dots.---------------------------------------and more, please contact me...<br>
<br>
nt|Boomerang Co., Ltd<br>
<!-- forum using plugin: "View more threads same category" of chiplove.9xpro -->
<h4 style="margin-top:1em">View more latest threads same category:</h4>
<ul style="margin:0.7em 2em;">
<li><a title="Phần mềm thám tử Kỳ Phát" href="showthread.php?49414">Phần mềm thám tử Kỳ Phát</a> </li>
<li><a title="Bảo hiểm nhân thọ Cathay" href="showthread.php?49143">Bảo hiểm nhân thọ Cathay</a> </li>
<li><a title="Theo dõi ngoại tình - Thám tử Kỳ Phát" href="showthread.php?48554">Theo dõi ngoại tình - Thám tử Kỳ Phát</a> </li>
<li><a title="VienLien247.com Sự chọn lựa đúng nhất và luôn có quà tặng đến với khách hàng" href="showthread.php?48332">VienLien247.com Sự chọn lựa đúng nhất và...</a> </li>
<li><a title="Công ty thám tử tư Kỳ Phát" href="showthread.php?48274">Công ty thám tử tư Kỳ Phát</a> </li>
<li><a title="Barcode Toolbox 3.6 for Illustrator CS4, CS 5" href="showthread.php?48121">Barcode Toolbox 3.6 for Illustrator CS4, CS 5</a> </li>
<li><a title="Bàn làm việc văn phòng" href="showthread.php?44824">Bàn làm việc văn phòng</a> </li>
<li><a title="Lịch sử ngành chế bản (P2)" href="showthread.php?44172">Lịch sử ngành chế bản (P2)</a> </li>
<li><a title="Lịch sử ngành chế bản" href="showthread.php?44170">Lịch sử ngành chế bản</a> </li>
<li><a title="Dotgain và bù dotgain trong chế bản điện tử" href="showthread.php?27575">Dotgain và bù dotgain trong chế bản điện tử</a> </li>
</ul>
Characteristics of AM and FM ScreeningThe digital revolution has brought a sea change to the prepress world, but the nature of the final printed product has hardly changed at all. Most color print matter with strong visual elements, such as brochures, pamphlets and magazines, is still printed using the same conventional 175 lpi Amplitude Modulation (AM) screening methods that were used before the digital revolution.Conventional AM screening reproduces light and darkness by varying the size of halftone dots. It is currently the screening method used most often in printing, because the pitch and angle of the dots are fixed, and the method achieves consistent tonal reproduction.Nevertheless, AM screening has drawbacks. Because the halftone dots are evenly spaced and at angles, AM screening is prone to moiré resulting from factors such as plate misalignment and interference patterns between screen angles and images. Other typical problems include jaggedness and segmenting of fine lines and tone jumping in gradation areas. These kinds of problems are particularly troublesome because they are generally not detectable prior to printing. These problems have also hindered the transition to fully digital workflows, the adoption of computer-to-plate (CTP), and the streamlining of the color proofing process. Efficiency-boosting measures such as direct digital color proofing, or using a color printer for proofing, remain problematic because of the risk of overlooking problems such as moiré.Trying to achieve higher print quality by using higher frequency AM screen rulings also has drawbacks, since printing with high-frequency screening requires much stricter print management conditions. This is why only a small minority of printers use high-frequency screens of 300 lpi or higher. And despite the spread of powerful graphics software that makes it simple to generate high-resolution data, the most common screening method in use, 175 lpi AM screening, leaves the graphic arts industry largely unable to get the most out of its detailed graphics and images.Frequency Modulation (FM) screening spent some time in the limelight as an alternative to conventional AM screening. FM screening places microdots of equal size randomly, varying their density to reproduce lightness and darkness. Not only does this approach eliminate the moiré and broken lines associated with AM screening, it also supports higher resolution printing. Unfortunately, FM screening demands a rigorous print production environment, which translates into higher printing costs. Also, in comparison to AM screening, with FM screening it is more difficult to print midtones and shadow areas consistently, and the midtones and highlights tend to appear grainy. Despite its other advantages over AM screening, FM screening’s own drawbacks have kept it from being more widely implemented.Spekta: Combining the strengths of AM and FM screeningDainippon Screen has taken the best qualities of both AM and FM screening, and melded them together in an innovative hybrid screening product, Spekta. Spekta overcomes the weaknesses of both FM and AM screening, while delivering their key strengths, to make highly-detailed, high-quality printing a reality using ordinary equipment. It uses AM-like dots or FM-like dots depending on the color density of each area being output. By doing so, it achieves the following remarkable characteristics:1. With the standard 2,400 dpi resolution that is typically used to output 175 lpi AM screens, Spekta achieves a level of detail comparable to high-frequency line screens of 300 lpi or higher. Moreover, it produces no jagged or broken lines.2. Spekta screening does not generate moiré because it creates no screen angles.3. It can be printed under standard printing conditions and there is no need to retrain operators.Varying the screening as required for each density rangeIn the 1–10% highlights and the 90–99% shadows, Spekta uses FM screening’s fixed dot size and reproduces tone by varying the density of uniform dots. In the 10–90% midtones, it varies the size of the round dots just as AM screening does. The placement of all these dots is random, as in FM Screening, however, which means there are no screen angles to contend with. As a result, Spekta avoids the moiré resulting from factors such as plate misalignment and interference patterns that plague conventional AM screening. Spekta overcomes the difficulty of printing FM screens by setting the size of the smallest dot slightly larger than in FM screens. It also minimizes tone jumping through advanced methods that control the positioning and joining of dots.---------------------------------------and more, please contact me...<br>
<br>
nt|Boomerang Co., Ltd<br>
<!-- forum using plugin: "View more threads same category" of chiplove.9xpro -->
<h4 style="margin-top:1em">View more latest threads same category:</h4>
<ul style="margin:0.7em 2em;">
<li><a title="Phần mềm thám tử Kỳ Phát" href="showthread.php?49414">Phần mềm thám tử Kỳ Phát</a> </li>
<li><a title="Bảo hiểm nhân thọ Cathay" href="showthread.php?49143">Bảo hiểm nhân thọ Cathay</a> </li>
<li><a title="Theo dõi ngoại tình - Thám tử Kỳ Phát" href="showthread.php?48554">Theo dõi ngoại tình - Thám tử Kỳ Phát</a> </li>
<li><a title="VienLien247.com Sự chọn lựa đúng nhất và luôn có quà tặng đến với khách hàng" href="showthread.php?48332">VienLien247.com Sự chọn lựa đúng nhất và...</a> </li>
<li><a title="Công ty thám tử tư Kỳ Phát" href="showthread.php?48274">Công ty thám tử tư Kỳ Phát</a> </li>
<li><a title="Barcode Toolbox 3.6 for Illustrator CS4, CS 5" href="showthread.php?48121">Barcode Toolbox 3.6 for Illustrator CS4, CS 5</a> </li>
<li><a title="Bàn làm việc văn phòng" href="showthread.php?44824">Bàn làm việc văn phòng</a> </li>
<li><a title="Lịch sử ngành chế bản (P2)" href="showthread.php?44172">Lịch sử ngành chế bản (P2)</a> </li>
<li><a title="Lịch sử ngành chế bản" href="showthread.php?44170">Lịch sử ngành chế bản</a> </li>
<li><a title="Dotgain và bù dotgain trong chế bản điện tử" href="showthread.php?27575">Dotgain và bù dotgain trong chế bản điện tử</a> </li>
</ul>