The Benefits
Below are listed some of the reasons why printers adopt FM/Stochastic screening for some, or all, of their presswork. In the adjacent posting I'll live going into to a greater extent than special on some of the benefits that receive got non been covered inwards past times posts on this topic.
1 - No concealment angle moiré
2 - No discipline moiré
3 - No rosettes
iv - Photographic/contone look Some examples are mentioned HERE
5 - Greater musical note in addition to color stability every bit SIDs naturally vary during press run
half-dozen - Larger color gamut The argue for the increased color gamut is explained inwards the post service HERE
7 - Faster drying
8 - Reduced ink usage - About 10-15% depending on musical note content of the presswork. The argue for reduced ink usage is explained HERE
nine - Tonal in addition to color stability when misregistration occurs
10 - Halftone dot construction stability when misregistration occurs
xi - Competitive differentiator
It's of import to sympathise that, when it comes to the press, how halftone dots are organized is non every bit of import every bit the size of the actual dot. As a result, some of the benefits of FM/Stochastic screening are available to conventional AM/XM screening if the lpi (halftone frequency) is fine enough. Specifically benefits 6, 7, in addition to 8 inwards the listing to a higher house tin move live delivered past times AM/XM screening if run at an equivalent lpi to the FM halftone. As a full general guide, the lithographic AM/XM/FM equivalents for a "second order" FM concealment at diverse dot sizes are shown below.
Color stability through the press run
Printing presses are stable - but non consistent. Solid ink densities volition naturally vary through the press run, in addition to when they practise 2 things happen; dot gain varies, in addition to ink density on the halftone dots varies. The outcome is variation inwards musical note in addition to color reproduction through the run.
When printers mensurate dot gain they mensurate it at the 50% musical note value rather than at the 1% or 2% signal because at roughly 50% dot gain variation is at its greatest.
The musical note variation happens because the large midtone dots inwards an AM/XM concealment tin move receive got to a greater extent than ink than the pocket-size dots inwards the highlights in addition to deep shadows. Put some other way, you lot can’t create a column of ink on a pocket-size dot, but the large dots roughly the 50% musical note tin move pick out on the ink so they volition grow the greatest. So, the midtone color gets darker in addition to lighter every bit enterprise ink density naturally varies through the press run.
However, the halftone dots inwards an FM concealment receive got a dissimilar ink profile.
FM screens effectively receive got pocket-size dots throughout the musical note range. They human activity much similar the highlight dots of an AM/XM concealment in addition to practise non pick out on every bit much extra ink every bit SIDs naturally vary - so they rest to a greater extent than stable in addition to thus the color remains to a greater extent than consistent through the run. For example, the below nautical chart shows the dot gain profile (solid line) of a 133 lpi AM/XM concealment in addition to a xx micron FM concealment calibrated to correspond that dot gain profile. The dashed lines demonstrate the dot gain answer when the enterprise ink density is raised past times thirty points (i.e. 1.40 to 1.70) to magnify the difference. The bend amongst the pocket-size dashes shows the answer of the FM screen, spell the longer dashed draw shows the answer of the AM/XM screen.
The color in addition to musical note stability that FM screening provides is similar to that provided past times heavy GCR color separations or ink reduction re-separation applications.
In some cases this on-press stability tin move live a 2 edged sword since, similar heavy GCR separations, it does non allow the press operator the mightiness to motility color quite every bit easily on press should the impress buyer create upward one's heed to live creative during a press approval. It also agency that if the press operator makes a SID change, the part of color/tone shift volition non live the same every bit that of an AM/XM screen.
That beingness said, consistency inwards color is usually the destination of presswork so the stability of FM screening is appreciated past times printers in addition to their customers every bit an splendid complement to their “print -by-the-numbers” goals.
Faster Ink Drying
One of the footling known benefits of FM screening is that it helps the presswork dry out faster. With FM screening, the tones are built amongst many pocket-size dots - effectively a “mist” rather than puddles of ink. The pocket-size FM dots send a thinner ink film, in addition to are distributed inwards a finer pattern that allows the ink to flash off its volatiles quicker causing the ink to dry out faster than their AM/XM counterparts.
To illustrate how this practise goodness is achieved, looking at the same concluding musical note value inwards the below image, on the left is a microphotograph of the large AM/XM dots spell on the right is magnified the smaller FM dots.
In the below icon I've taken those microphotographs of the dots in addition to passed them through a 3D rendering programme that translates density into superlative to reckon exactly how thick the ink cinema is. As you lot tin move reckon on the right, for the same concluding musical note the FM concealment has a thinner cinema of ink than the AM/XM dot.
The faster drying tin move also live demonstrated amongst a unproblematic test. Below are 3 images printed on uncoated mass stock, the lefthand icon is 133 lpi, the pump is 200 lpi, in addition to the righhand icon xx micron FM. I so used a money to scratch across the 3/C slope every bit before long every bit the canvas came off the press:
It's rattling slow to reckon the marks made past times the money inwards the 133 in addition to 200 lpi slope - spell the FM slope is almost completely dry out in addition to hardly shows whatever marks from the money at all.
The faster drying of FM screening brings other benefits, namely:
1- It's easier to align presswork amongst proof - since they are both dry out 1 doesn't receive got to draw of piece of work organisation human relationship for dryback
2 - Reduced setoff
3 - Prints improve on uncoated, newsprint, foils in addition to plastics
iv - Less spray pulverization is needed
v - Less distortion on perfecting presses
half-dozen - Jobs are faster to bindery
seven - Heatset presses may live able to lower their drying ovens a few degrees in addition to thus salve on release energy costs
LPI Integrity
Even though most printers receive got experienced the problem, few receive got understood it. LPI integrity is a practise goodness of FM/Stochastic screening that may live a fleck hard to sympathise at first.
AM/XM screens generate a rosette pattern when all the screens are at the right angles. Influenza A virus subtype H5N1 rosette is a high frequency moiré in addition to every bit such is rattling unstable. If in that place is a slight misregistration, what happens is that the rosette pattern of the AM/XM concealment changes - typically from clear-centered to dot centered. The adjacent few images demonstrate the results of a one-half row shift inwards mis-registration:
As the rosette shifts from beingness clear-centered to beingness dot-centered - the visibility of the rosette changes. Effectively, the rosette shifts from beingness high frequency to depression frequency. Put some other way, the effective lpi of the halftone tin move shift from a fine 175 lpi to a coarse 85 lpi every bit a outcome of slight misregistration. So, a rosette pattern that occurs inwards of import pare colors may non live visible when inwards register, all of a abrupt becomes rattling visible amongst slight misregistration. However, FM screens practise non make rosettes in addition to every bit a outcome they keep their lpi icon integrity when slight misregistration naturally occurs.
Color Integrity When Misregistration Occurs
You tin move receive got the best presses in addition to the best plate imaging available, however, because you lot are roofing a canvas of paper amongst a mix of stone oil in addition to water, squeezing in addition to pulling it through the press - some amount of misregistration is an inevitable fact of press life. The acquit on of that misregistration on color in addition to musical note reproduction volition depend on whether you lot are using an AM/XM or FM screen.
Here is a total sized image:
And here, enlarged, is a department of the icon using an AM/XM concealment on the left in addition to an FM concealment on the right. Both are inwards register.
And hither is the same department but amongst the Magenta for both screens out of register past times a one-half row of dots (1/300th of an inch) - considered inside normal printing tolerances.
Notice how the dot construction inwards the rosette visibly changes inwards the AM/XM concealment (175 lpi inwards this case) when it's out of register but the FM concealment (20 micron inwards this case) remains stable since it does non receive got a rosette.
More importantly authorities annotation the modify inwards AM/XM rosette construction from clear-centered to dot-centered in addition to dorsum to clear-centered every bit it drifts inwards in addition to out out of register. It’s similar turning a low-cal on in addition to off in addition to dorsum 1 time to a greater extent than - so the color goes darker in addition to lighter in addition to darker in addition to lighter through the run.
Also, misregistration changes the overprint in addition to ratios of moisture in addition to dry out trap. Influenza A virus subtype H5N1 blueish made from Cyan in addition to Magenta dots beside each other is non the same blueish every bit when Magenta dots overprint the Cyan. The outcome is a color shift. So spell the AM/XM presswork is going darker in addition to lighter it is also shifting color from bluish to redish in addition to dorsum 1 time to a greater extent than every bit slight misregistration occurs. This tin move live especially troublesome in, for example, auto brochures where in that place are large expansive areas of neutral greyness made upward of 4/c process. Again, since FM screens don’t receive got a rosette the color in addition to musical note are improve preserved amongst natural slight misregistration inwards presswork.
The bottom draw - FM screening tin move assist deliver to a greater extent than presswork color consistency - which, afterwards all, is 1 of the principal goals of printing.
Potential Issues
So far it's all expert - but what nearly the potential downsides of FM/Stochastic screening?
Influenza A virus subtype H5N1 printing press or plate does non "know" how a pattern of halftone dots is arranged - it does non know whether the screening is AM/XM or FM. So, the problems related to FM screening are non usually the outcome of the halftone pattern itself, but past times the size of the dots that brand upward the halftone screen. In that respect, FM screening shares the same problems associated amongst whatever high frequency halftone - FM or AM/XM.
This former Planeta press prints breakfast cereal boxes using FM screening for press runs that tin move finally a week.
This novel KBA press prints daily newspapers, inserts/flyers in addition to commercial operate using FM screening exclusively.
Here are some of the issues that tin move arise using FM in addition to AM/XM screening.
1 - Grainy appearance inwards apartment tint areas. This usually doesn't occur amongst AM/XM. There are several possible causes:
1) Poor concealment pattern and/or using a commencement lodge FM concealment pattern (see HERE for explanation). This work has been overcome past times modern minute lodge FM screens.
2) Graininess tin move also outcome from a lack of plate imaging integrity e.g. plate doesn't receive got a high plenty resolution for the dot size beingness used, in addition to inconsistent plate imaging. Again it by in addition to large occurs amongst older commencement lodge FM concealment designs. Graininess tin move also occur when screening dorsum a topographic point color. This is because topographic point colors are commonly non formulated to live halftone screened in addition to thus their paint grind may live also coarse for the dot size beingness used.
2 - Inability to align presswork color to an manufacture measure similar SWOP, GRACoL7, etc. The higher the halftone concealment frequency, AM/XM or FM, the larger the color gamut becomes (this is explained HERE and HERE). The extra gamut appears inwards 1 in addition to 2 color concealment tint builds making them appear to a greater extent than vibrant than the same concealment tint create using a lower lpi AM/XM concealment (e.g. 175 lpi). It usually only effects vector artwork in addition to typically does non demonstrate upward inwards raster images. If this is a work it tin move live dealt amongst using color administration in addition to re-separating images to contaminate color builds to cut the gamut. Unexpected color shifts tin move also occur when screening dorsum a topographic point color. This is because topographic point colors are commonly non formulated to live halftone screened in addition to thus the acquit on of using a high frequency screen, amongst its increased gamut tin move atomic number 82 to an unexpected concluding color appearance.
3 - Piling. Piling may occur on heatset spider web presses in addition to is usually caused past times non next proper blanket washup schedules or past times miserable ink rheology - i.e. using inks formulated for the large dots of a coarse AM/XM concealment rather than formulated for the smaller FM dots. Piling is rare on sheetfed presses - typically an ik that works amongst a 200 lpi AM/XM concealment volition operate amongst a 20-25 micron FM screen.
4 - Mottle. Mottle (splotchy appearance of apartment musical note areas) tin move appear amongst whatever high frequency screen. It is usually the outcome miserable ink transfer (incorrect ink formulation), outflow solution condition, or paper surface/coating characteristics. Mottle tin move also occur when screening dorsum a topographic point color. This is because topographic point colors are commonly non formulated to live halftone screened in addition to thus their paint grind may live also coarse for the dot size beingness used.
5 - Poor icon reproduction. The higher the lpi of the screen, AM/XM or FM, the higher the special rendering in addition to thus the improve the detail, flaws, in addition to artifacts of an master icon are reproduced. Another work tin move live a "softness" to the icon reproduction. This is usually caused when high dpi images are resampled to a lower resolution when the PDF is created or resampled when the icon goes through the RIP. The solution is to non resample images.
half-dozen - General failure. The most mutual reasons that crusade printers to neglect amongst FM in addition to high frequency AM/FM screening that I've encountered are:
1) Poor procedure command inwards the shop. Halftone screening inwards the make of 65-175 lpi is rattling tolerant of procedure variations nonetheless every bit the dots teach smaller, procedure controls postulate to live tighter. That beingness said, the procedure controls that postulate to live inwards house for FM screening to succeed are no dissimilar than those needed for an efficient 175 lpi impress manufacturing process. If in that place are whatever issues - high frequency screening volition brand those issues to a greater extent than visible.
2) Lack of buy-in. If the frontline people (e.g. prepress and/or press operators) receive got non bought into the sentiment of using FM screening - it volition fail. Without buy-in the modify exactly represents a disruption to what they reckon every bit a polish running process. "Why develop it if it ain't broke?"
3) Lack of use. If FM screening is only used for "special jobs" so press operators never teach used to how it performs on press in addition to every bit a outcome they volition fighting amongst it. As amongst most activities, the to a greater extent than you lot practise them the improve you lot teach at doing them. It is best if the store makes the commitment to modify to FM in addition to brand traditional AM/XM screening the special representative exception.
In hereafter posts I volition live roofing success strategies for implementing FM screening every bit good every bit full general procedure command proceedures.
About 80% of all the directory printing inwards North America is done using FM screening.
Below are listed some of the reasons why printers adopt FM/Stochastic screening for some, or all, of their presswork. In the adjacent posting I'll live going into to a greater extent than special on some of the benefits that receive got non been covered inwards past times posts on this topic.1 - No concealment angle moiré
2 - No discipline moiré
3 - No rosettes
iv - Photographic/contone look Some examples are mentioned HERE
5 - Greater musical note in addition to color stability every bit SIDs naturally vary during press run
half-dozen - Larger color gamut The argue for the increased color gamut is explained inwards the post service HERE
7 - Faster drying
8 - Reduced ink usage - About 10-15% depending on musical note content of the presswork. The argue for reduced ink usage is explained HERE
nine - Tonal in addition to color stability when misregistration occurs
10 - Halftone dot construction stability when misregistration occurs
xi - Competitive differentiator
It's of import to sympathise that, when it comes to the press, how halftone dots are organized is non every bit of import every bit the size of the actual dot. As a result, some of the benefits of FM/Stochastic screening are available to conventional AM/XM screening if the lpi (halftone frequency) is fine enough. Specifically benefits 6, 7, in addition to 8 inwards the listing to a higher house tin move live delivered past times AM/XM screening if run at an equivalent lpi to the FM halftone. As a full general guide, the lithographic AM/XM/FM equivalents for a "second order" FM concealment at diverse dot sizes are shown below.
Color stability through the press run
Printing presses are stable - but non consistent. Solid ink densities volition naturally vary through the press run, in addition to when they practise 2 things happen; dot gain varies, in addition to ink density on the halftone dots varies. The outcome is variation inwards musical note in addition to color reproduction through the run.
When printers mensurate dot gain they mensurate it at the 50% musical note value rather than at the 1% or 2% signal because at roughly 50% dot gain variation is at its greatest.
The musical note variation happens because the large midtone dots inwards an AM/XM concealment tin move receive got to a greater extent than ink than the pocket-size dots inwards the highlights in addition to deep shadows. Put some other way, you lot can’t create a column of ink on a pocket-size dot, but the large dots roughly the 50% musical note tin move pick out on the ink so they volition grow the greatest. So, the midtone color gets darker in addition to lighter every bit enterprise ink density naturally varies through the press run.However, the halftone dots inwards an FM concealment receive got a dissimilar ink profile.
FM screens effectively receive got pocket-size dots throughout the musical note range. They human activity much similar the highlight dots of an AM/XM concealment in addition to practise non pick out on every bit much extra ink every bit SIDs naturally vary - so they rest to a greater extent than stable in addition to thus the color remains to a greater extent than consistent through the run. For example, the below nautical chart shows the dot gain profile (solid line) of a 133 lpi AM/XM concealment in addition to a xx micron FM concealment calibrated to correspond that dot gain profile. The dashed lines demonstrate the dot gain answer when the enterprise ink density is raised past times thirty points (i.e. 1.40 to 1.70) to magnify the difference. The bend amongst the pocket-size dashes shows the answer of the FM screen, spell the longer dashed draw shows the answer of the AM/XM screen.
The color in addition to musical note stability that FM screening provides is similar to that provided past times heavy GCR color separations or ink reduction re-separation applications.
In some cases this on-press stability tin move live a 2 edged sword since, similar heavy GCR separations, it does non allow the press operator the mightiness to motility color quite every bit easily on press should the impress buyer create upward one's heed to live creative during a press approval. It also agency that if the press operator makes a SID change, the part of color/tone shift volition non live the same every bit that of an AM/XM screen.
That beingness said, consistency inwards color is usually the destination of presswork so the stability of FM screening is appreciated past times printers in addition to their customers every bit an splendid complement to their “print -by-the-numbers” goals.Faster Ink Drying
One of the footling known benefits of FM screening is that it helps the presswork dry out faster. With FM screening, the tones are built amongst many pocket-size dots - effectively a “mist” rather than puddles of ink. The pocket-size FM dots send a thinner ink film, in addition to are distributed inwards a finer pattern that allows the ink to flash off its volatiles quicker causing the ink to dry out faster than their AM/XM counterparts.
To illustrate how this practise goodness is achieved, looking at the same concluding musical note value inwards the below image, on the left is a microphotograph of the large AM/XM dots spell on the right is magnified the smaller FM dots.
In the below icon I've taken those microphotographs of the dots in addition to passed them through a 3D rendering programme that translates density into superlative to reckon exactly how thick the ink cinema is. As you lot tin move reckon on the right, for the same concluding musical note the FM concealment has a thinner cinema of ink than the AM/XM dot.
The faster drying tin move also live demonstrated amongst a unproblematic test. Below are 3 images printed on uncoated mass stock, the lefthand icon is 133 lpi, the pump is 200 lpi, in addition to the righhand icon xx micron FM. I so used a money to scratch across the 3/C slope every bit before long every bit the canvas came off the press:
It's rattling slow to reckon the marks made past times the money inwards the 133 in addition to 200 lpi slope - spell the FM slope is almost completely dry out in addition to hardly shows whatever marks from the money at all.
The faster drying of FM screening brings other benefits, namely:
1- It's easier to align presswork amongst proof - since they are both dry out 1 doesn't receive got to draw of piece of work organisation human relationship for dryback
2 - Reduced setoff
3 - Prints improve on uncoated, newsprint, foils in addition to plastics
iv - Less spray pulverization is needed
v - Less distortion on perfecting presses
half-dozen - Jobs are faster to bindery
seven - Heatset presses may live able to lower their drying ovens a few degrees in addition to thus salve on release energy costs
LPI Integrity
Even though most printers receive got experienced the problem, few receive got understood it. LPI integrity is a practise goodness of FM/Stochastic screening that may live a fleck hard to sympathise at first.
AM/XM screens generate a rosette pattern when all the screens are at the right angles. Influenza A virus subtype H5N1 rosette is a high frequency moiré in addition to every bit such is rattling unstable. If in that place is a slight misregistration, what happens is that the rosette pattern of the AM/XM concealment changes - typically from clear-centered to dot centered. The adjacent few images demonstrate the results of a one-half row shift inwards mis-registration:
As the rosette shifts from beingness clear-centered to beingness dot-centered - the visibility of the rosette changes. Effectively, the rosette shifts from beingness high frequency to depression frequency. Put some other way, the effective lpi of the halftone tin move shift from a fine 175 lpi to a coarse 85 lpi every bit a outcome of slight misregistration. So, a rosette pattern that occurs inwards of import pare colors may non live visible when inwards register, all of a abrupt becomes rattling visible amongst slight misregistration. However, FM screens practise non make rosettes in addition to every bit a outcome they keep their lpi icon integrity when slight misregistration naturally occurs.Color Integrity When Misregistration Occurs
You tin move receive got the best presses in addition to the best plate imaging available, however, because you lot are roofing a canvas of paper amongst a mix of stone oil in addition to water, squeezing in addition to pulling it through the press - some amount of misregistration is an inevitable fact of press life. The acquit on of that misregistration on color in addition to musical note reproduction volition depend on whether you lot are using an AM/XM or FM screen.
Here is a total sized image:
And here, enlarged, is a department of the icon using an AM/XM concealment on the left in addition to an FM concealment on the right. Both are inwards register.
And hither is the same department but amongst the Magenta for both screens out of register past times a one-half row of dots (1/300th of an inch) - considered inside normal printing tolerances.
Notice how the dot construction inwards the rosette visibly changes inwards the AM/XM concealment (175 lpi inwards this case) when it's out of register but the FM concealment (20 micron inwards this case) remains stable since it does non receive got a rosette.
More importantly authorities annotation the modify inwards AM/XM rosette construction from clear-centered to dot-centered in addition to dorsum to clear-centered every bit it drifts inwards in addition to out out of register. It’s similar turning a low-cal on in addition to off in addition to dorsum 1 time to a greater extent than - so the color goes darker in addition to lighter in addition to darker in addition to lighter through the run.
Also, misregistration changes the overprint in addition to ratios of moisture in addition to dry out trap. Influenza A virus subtype H5N1 blueish made from Cyan in addition to Magenta dots beside each other is non the same blueish every bit when Magenta dots overprint the Cyan. The outcome is a color shift. So spell the AM/XM presswork is going darker in addition to lighter it is also shifting color from bluish to redish in addition to dorsum 1 time to a greater extent than every bit slight misregistration occurs. This tin move live especially troublesome in, for example, auto brochures where in that place are large expansive areas of neutral greyness made upward of 4/c process. Again, since FM screens don’t receive got a rosette the color in addition to musical note are improve preserved amongst natural slight misregistration inwards presswork.
The bottom draw - FM screening tin move assist deliver to a greater extent than presswork color consistency - which, afterwards all, is 1 of the principal goals of printing.
Potential Issues
So far it's all expert - but what nearly the potential downsides of FM/Stochastic screening?Influenza A virus subtype H5N1 printing press or plate does non "know" how a pattern of halftone dots is arranged - it does non know whether the screening is AM/XM or FM. So, the problems related to FM screening are non usually the outcome of the halftone pattern itself, but past times the size of the dots that brand upward the halftone screen. In that respect, FM screening shares the same problems associated amongst whatever high frequency halftone - FM or AM/XM.
Here are some of the issues that tin move arise using FM in addition to AM/XM screening.
1 - Grainy appearance inwards apartment tint areas. This usually doesn't occur amongst AM/XM. There are several possible causes:
1) Poor concealment pattern and/or using a commencement lodge FM concealment pattern (see HERE for explanation). This work has been overcome past times modern minute lodge FM screens.
2) Graininess tin move also outcome from a lack of plate imaging integrity e.g. plate doesn't receive got a high plenty resolution for the dot size beingness used, in addition to inconsistent plate imaging. Again it by in addition to large occurs amongst older commencement lodge FM concealment designs. Graininess tin move also occur when screening dorsum a topographic point color. This is because topographic point colors are commonly non formulated to live halftone screened in addition to thus their paint grind may live also coarse for the dot size beingness used.
2 - Inability to align presswork color to an manufacture measure similar SWOP, GRACoL7, etc. The higher the halftone concealment frequency, AM/XM or FM, the larger the color gamut becomes (this is explained HERE and HERE). The extra gamut appears inwards 1 in addition to 2 color concealment tint builds making them appear to a greater extent than vibrant than the same concealment tint create using a lower lpi AM/XM concealment (e.g. 175 lpi). It usually only effects vector artwork in addition to typically does non demonstrate upward inwards raster images. If this is a work it tin move live dealt amongst using color administration in addition to re-separating images to contaminate color builds to cut the gamut. Unexpected color shifts tin move also occur when screening dorsum a topographic point color. This is because topographic point colors are commonly non formulated to live halftone screened in addition to thus the acquit on of using a high frequency screen, amongst its increased gamut tin move atomic number 82 to an unexpected concluding color appearance.
3 - Piling. Piling may occur on heatset spider web presses in addition to is usually caused past times non next proper blanket washup schedules or past times miserable ink rheology - i.e. using inks formulated for the large dots of a coarse AM/XM concealment rather than formulated for the smaller FM dots. Piling is rare on sheetfed presses - typically an ik that works amongst a 200 lpi AM/XM concealment volition operate amongst a 20-25 micron FM screen.
4 - Mottle. Mottle (splotchy appearance of apartment musical note areas) tin move appear amongst whatever high frequency screen. It is usually the outcome miserable ink transfer (incorrect ink formulation), outflow solution condition, or paper surface/coating characteristics. Mottle tin move also occur when screening dorsum a topographic point color. This is because topographic point colors are commonly non formulated to live halftone screened in addition to thus their paint grind may live also coarse for the dot size beingness used.
5 - Poor icon reproduction. The higher the lpi of the screen, AM/XM or FM, the higher the special rendering in addition to thus the improve the detail, flaws, in addition to artifacts of an master icon are reproduced. Another work tin move live a "softness" to the icon reproduction. This is usually caused when high dpi images are resampled to a lower resolution when the PDF is created or resampled when the icon goes through the RIP. The solution is to non resample images.
half-dozen - General failure. The most mutual reasons that crusade printers to neglect amongst FM in addition to high frequency AM/FM screening that I've encountered are:
1) Poor procedure command inwards the shop. Halftone screening inwards the make of 65-175 lpi is rattling tolerant of procedure variations nonetheless every bit the dots teach smaller, procedure controls postulate to live tighter. That beingness said, the procedure controls that postulate to live inwards house for FM screening to succeed are no dissimilar than those needed for an efficient 175 lpi impress manufacturing process. If in that place are whatever issues - high frequency screening volition brand those issues to a greater extent than visible.
2) Lack of buy-in. If the frontline people (e.g. prepress and/or press operators) receive got non bought into the sentiment of using FM screening - it volition fail. Without buy-in the modify exactly represents a disruption to what they reckon every bit a polish running process. "Why develop it if it ain't broke?"
3) Lack of use. If FM screening is only used for "special jobs" so press operators never teach used to how it performs on press in addition to every bit a outcome they volition fighting amongst it. As amongst most activities, the to a greater extent than you lot practise them the improve you lot teach at doing them. It is best if the store makes the commitment to modify to FM in addition to brand traditional AM/XM screening the special representative exception.
In hereafter posts I volition live roofing success strategies for implementing FM screening every bit good every bit full general procedure command proceedures.
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