4000 ppi

[Magnet]

It's now possible to have 4000 ppi on EskoArtwork's CtP imagers.
What are the advantages of this 4000 ppi?


Greets

 

[claude72]

What are the advantages of this 4000 ppi?

Sorry, but your unit is not the right one : PPI means Pixels Per Inch, and pixels are for pictures! (pixel = picture element)

But an imagesetter or a printer (laser or ink-jet) prints dots (not pixels!), and then the correct unit for the resolution of a printing device is DPI (Dots Per Inch).

********

20 years ago, raising the resolution above 2400 dpi had the advantage to get the 256 levels at screen frequencies higher than 150 lpi: 4000 dpi should have allow to print up to a 250 lpi screen with 256 levels...

Today and since the beginning of the 90's, the SuperCells screening technology allows to get the 256 levels of a 250 lpi screen with only 3000 dpi or less.
(read Gordo's blog for more explanations on SuperCells).
But even with SuperCells screening there is still a limit to the highest screen frequency that can be outputted with a given resolution, and having an higher resolution still allows higher screen frequencies...

(for example, my imagesetter outputs screens up to 200 lpi at 2400 dpi, and needs it's 3600 dpi highest resolution for higher screen frequencies, up to 425 lpi...
... but who can print a 425 lpi screen with an offset press??? )

 

[marktonk]

The higehr DPI may be needed for certain security printing. We offer a 5080 DPI option on the Suprasetter for this reason. See enclosed link

Heidelberg - IPEX 2010 – Heidelberg Expands Suprasetter A52/A75 Family

 

[DavidH]

As is explained very well in Gordo's blog, supercell screening removed the original gray level limitation and, as a result, mainstream imaging resolutions have reached a plateau at around 2540 dpi. For offset litho CTP, there is no clear benefit in using a higher resolution for most applications (there are special cases such as security printing).

In relief printing processes - flexography and letterpress - there are significant benefits to be gained by imaging the plates at higher resolution. By forming rounder more stable dots on the polymer, print consistency can be increased and tonal range improved.

Esko Artwork have published a white paper setting out our reasoning on this (attached below).

David Harris
Product Manager, Esko Artwork