Esko Concentric screening is at view an AM covert which uses a unique halftone dot where enterprise AM dots are divided into sparse concentric rings.
Click on the to a higher house epitome to run across it enlarged.
Concentric screening too colouring cloth gamut
Chroma inwards press operate derives primarily from the ratio of calorie-free beingness filtered past times ink carried on halftone dots vs calorie-free reflected off the newspaper that hasn't been filtered past times the ink. Light that is unfiltered past times the ink effectively contaminates the colouring cloth reducing the potential gamut of the inks. If 1 compares Concentric halftone dots amongst conventional AM/XM halftone dots at the same lpi - e.g. 175 lpi. what is clear is the deviation inwards ink coverage expanse through which calorie-free tin strength out survive filtered.
At left is a micro photograph of Esko Concentric too on the correct is an AM/XM covert (Esko Paragon). Both are imaged at 175 lpi.
Note that dividing the dot into rings genuinely lessens the expanse of ink too increases the expanse of unprinted paper. Effectively it increases the contamination of colouring cloth past times calorie-free reflected off of the unprinted substrate which tin strength out genuinely reduce, rather than increase, the potential gamut.
In the below plot, the CIEL*a*b* values of the same musical note values for 175 lpi AM/XM/Paragon screening (in green) is compared to 175 lpi Concentric (in red). If the Concentric had a larger gamut the ruby dots would survive significantly to a higher house the light-green dots indicating a greater chroma. Instead they rail at, or are below, the chroma for 175 lpi AM/XM/Esko Paragon screening.
What this agency is that, every bit far every bit I tin strength out determine, Concentric screening offers no additional gamut, too mayhap less of a gamut, when it is compared amongst AM/XM screens at the same lpi.
Concentric screening too epitome quality
Since it is all the same an AM covert in that location is all the same the chance for screening too dependent plain moiré - although the finer the covert (AM/XM or Concentric) the less probable that volition survive a problem. Because it's all the same an AM halftone covert it has rosettes - only similar whatever other AM/XM covert - formed past times the covert angles.
At left Esko Paragon AM rosettes. At correct Esko Concentric rosettes. Both screens are 175 lpi. (Squint your eyes or displace a few feet away from the covert to brand the rosettes to a greater extent than prominent.)
From a impress buyer indicate of thought in that location volition probable survive no visible deviation betwixt a 200-300 lpi conventional AM/XM covert too Concentric screening - fifty-fifty if viewed nether a loupe.
Concentric screening too ink reduction
The 2 principal causes of the reduction inwards ink usage amongst high lpi screens are the thinner ink films too the demand for musical note reproduction curves for plate imaging to select the press musical note reply inwards business amongst the measure 175 lpi AM/XM screening. Ink reduction amongst the purpose of Concentric screening should survive similar to the ink reduction enjoyed past times high lpi conventional AM/XM likewise every bit FM screens.
Concentric screening too on press colouring cloth stability
Greater colouring cloth stability when enterprise ink densities naturally vary during the press run is a feature of high frequency screening (i.e. smaller dots) whether AM/XM, FM or Concentric. The actual ink cinema thickness of Concentric vs conventional AM/XM screening at the same lpi is genuinely real similar. Projecting dot density to summit inwards 3D 1 tin strength out run across this quite clearly (Concentric is left of the dark business - AM/XM is correct of the dark line.)
Of course, if the Concentric screening is run at a real high lpi it volition larn a stability that is similar to conventional screens (AM/XM too FM) that are run to the same high frequency.
Concentric screening too imaging organization resolution
Concentric screening is effectively an AM covert ruling multiplier. What this agency is that the resolution of the imaging organization needs to survive able to epitome the minimum specified band width. Put to a greater extent than or less other way, if the band thickness called for is 10 microns broad too then the imaging organization (plate too press) must survive capable of consistently imaging a 10 micron pixel/dot fifty-fifty though the actual concluding halftone dot size may survive virtually 5 times wider (e.g. 48 microns broad a 50% dot at 250 lpi).
Concentric halftone dots that depend on 1-2 pixel width imaging integrity tin strength out survive problematic for most imaging systems
As a result, using Concentric screeing tin strength out force the effective covert frequency thus high that procedure stability too imaging may survive compromised too it tin strength out survive hard to back upward their purpose on plate allow lonely notice a way to implement them inwards the press room. The employment is that to a greater extent than or less concentric covert settings tin strength out drive rulings way over what plate imaging tin strength out back upward - on the fellowship of 1-2 pixel widths for the rings, which is understandably problematic. For example, a 200 lpi covert amongst 2 pixel ringwidths = 600 lpi which is finer than, for example, a 10 micron FM screen.
Coarser ringwidths are easier to back upward but at that indicate it is in all likelihood to a greater extent than effective to purpose an AM covert of equivalent lpi.
For printers contemplating the adoption of Concentric screening
Since Concentric screening is a conventional AM covert using a unique halftone dot design, I advise that when you lot are evaluating this type of screening that you lot "compare apples to apples". That agency that you lot should compare the on press surgery of Concentric against a conventional AM/XM covert imaged at the same lpi. Use a combination of subjective (pretty pictures) likewise every bit objective measurable targets (single too 2 colouring cloth footstep wedge gradients too IT8 profiling targets).
N.B. The information that I used every bit the footing for this post is derived from published promotional samples printed past times Esko. I accept contacted Esko likewise every bit members of world prepress/press forums yell for for press profiles and/or printed attempt out samples of Concentric vs conventional AM/XM screens run at the same lpi nether the same press conditions. Despite the production beingness inwards the marketplace position for over 4 years I accept been unable to larn such a basic colouring cloth profile or press samples. If you lot accept that information I would appreciate hearing from you lot past times e-mail ( pritchardgordon @ gmail (dot) com ).
Concentric screening too colouring cloth gamut
Chroma inwards press operate derives primarily from the ratio of calorie-free beingness filtered past times ink carried on halftone dots vs calorie-free reflected off the newspaper that hasn't been filtered past times the ink. Light that is unfiltered past times the ink effectively contaminates the colouring cloth reducing the potential gamut of the inks. If 1 compares Concentric halftone dots amongst conventional AM/XM halftone dots at the same lpi - e.g. 175 lpi. what is clear is the deviation inwards ink coverage expanse through which calorie-free tin strength out survive filtered.
Note that dividing the dot into rings genuinely lessens the expanse of ink too increases the expanse of unprinted paper. Effectively it increases the contamination of colouring cloth past times calorie-free reflected off of the unprinted substrate which tin strength out genuinely reduce, rather than increase, the potential gamut.
In the below plot, the CIEL*a*b* values of the same musical note values for 175 lpi AM/XM/Paragon screening (in green) is compared to 175 lpi Concentric (in red). If the Concentric had a larger gamut the ruby dots would survive significantly to a higher house the light-green dots indicating a greater chroma. Instead they rail at, or are below, the chroma for 175 lpi AM/XM/Esko Paragon screening.
What this agency is that, every bit far every bit I tin strength out determine, Concentric screening offers no additional gamut, too mayhap less of a gamut, when it is compared amongst AM/XM screens at the same lpi.
Concentric screening too epitome quality
Since it is all the same an AM covert in that location is all the same the chance for screening too dependent plain moiré - although the finer the covert (AM/XM or Concentric) the less probable that volition survive a problem. Because it's all the same an AM halftone covert it has rosettes - only similar whatever other AM/XM covert - formed past times the covert angles.
From a impress buyer indicate of thought in that location volition probable survive no visible deviation betwixt a 200-300 lpi conventional AM/XM covert too Concentric screening - fifty-fifty if viewed nether a loupe.
Concentric screening too ink reduction
The 2 principal causes of the reduction inwards ink usage amongst high lpi screens are the thinner ink films too the demand for musical note reproduction curves for plate imaging to select the press musical note reply inwards business amongst the measure 175 lpi AM/XM screening. Ink reduction amongst the purpose of Concentric screening should survive similar to the ink reduction enjoyed past times high lpi conventional AM/XM likewise every bit FM screens.
Concentric screening too on press colouring cloth stability
Greater colouring cloth stability when enterprise ink densities naturally vary during the press run is a feature of high frequency screening (i.e. smaller dots) whether AM/XM, FM or Concentric. The actual ink cinema thickness of Concentric vs conventional AM/XM screening at the same lpi is genuinely real similar. Projecting dot density to summit inwards 3D 1 tin strength out run across this quite clearly (Concentric is left of the dark business - AM/XM is correct of the dark line.)
Of course, if the Concentric screening is run at a real high lpi it volition larn a stability that is similar to conventional screens (AM/XM too FM) that are run to the same high frequency.Concentric screening too imaging organization resolution
Concentric screening is effectively an AM covert ruling multiplier. What this agency is that the resolution of the imaging organization needs to survive able to epitome the minimum specified band width. Put to a greater extent than or less other way, if the band thickness called for is 10 microns broad too then the imaging organization (plate too press) must survive capable of consistently imaging a 10 micron pixel/dot fifty-fifty though the actual concluding halftone dot size may survive virtually 5 times wider (e.g. 48 microns broad a 50% dot at 250 lpi).
As a result, using Concentric screeing tin strength out force the effective covert frequency thus high that procedure stability too imaging may survive compromised too it tin strength out survive hard to back upward their purpose on plate allow lonely notice a way to implement them inwards the press room. The employment is that to a greater extent than or less concentric covert settings tin strength out drive rulings way over what plate imaging tin strength out back upward - on the fellowship of 1-2 pixel widths for the rings, which is understandably problematic. For example, a 200 lpi covert amongst 2 pixel ringwidths = 600 lpi which is finer than, for example, a 10 micron FM screen.
Coarser ringwidths are easier to back upward but at that indicate it is in all likelihood to a greater extent than effective to purpose an AM covert of equivalent lpi.
For printers contemplating the adoption of Concentric screening
Since Concentric screening is a conventional AM covert using a unique halftone dot design, I advise that when you lot are evaluating this type of screening that you lot "compare apples to apples". That agency that you lot should compare the on press surgery of Concentric against a conventional AM/XM covert imaged at the same lpi. Use a combination of subjective (pretty pictures) likewise every bit objective measurable targets (single too 2 colouring cloth footstep wedge gradients too IT8 profiling targets).
N.B. The information that I used every bit the footing for this post is derived from published promotional samples printed past times Esko. I accept contacted Esko likewise every bit members of world prepress/press forums yell for for press profiles and/or printed attempt out samples of Concentric vs conventional AM/XM screens run at the same lpi nether the same press conditions. Despite the production beingness inwards the marketplace position for over 4 years I accept been unable to larn such a basic colouring cloth profile or press samples. If you lot accept that information I would appreciate hearing from you lot past times e-mail ( pritchardgordon @ gmail (dot) com ).
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