Kodak Gen News

[Shediac]

The company has purchased 2 Kodak Gen News V speed. They are 1200 DPI machines. Will we be able to output a 133 line screen?

[ARIL]

Yes, Please It's something new on cpt(news)-prepress? I'm intresting on that information.
Thank you wery much!!!

[Kevin@Kodak]

The company has purchased 2 Kodak Gen News V speed. They are 1200 DPI machines. Will we be able to output a 133 line screen?

Shediac - because we use a 5000dpi SQUAREspot imaging head to achieve 1200dpi output resolution, we draw those dots EXTREMELY precisely. This allows us to support up to 200lpi hybrid AM screening at 1200dpi, or 36 micron FM screening.

Of course, this is also dependent on the plate you choose, but 133lpi is no problem on most thermal newspaper plates.


Kevin.

[gordo]

Shediac - because we use a 5000dpi SQUAREspot imaging head to achieve 1200dpi output resolution, we draw those dots EXTREMELY precisely. This allows us to support up to 200lpi hybrid AM screening at 1200dpi, or 36 micron FM screening.

Of course, this is also dependent on the plate you choose, but 133lpi is no problem on most thermal newspaper plates.

Kevin.

I have to disagree with Kevin on this one.

Shediac is likely concerned about achieving all the grey levels needed for 133 lpi screening on a 1200 dpi device.
The classic formula to determine grey levels is:
(dpi/lpi) squared + 1 = number of grey levels

So for 133 lpi at 1200 dpi:

1200 dpi/133 = 9
9 squared = 81
91 + 1 = only 82 possible tones

However, since about 1985, Supercell screening (a function of the RIP not the output device resolution) has eliminated the grey levels limitation by "dithering" the halftone dots. This type of conventional AM screening is available, if not the standard, from all the vendors - including Kodak.

Here are some of the popular brand names:

Agfa - ABS - Agfa Balanced Screening
Heidelberg - HDS - High Definition Screening, and later IS screening
Harlequin - HPS - Harlequin Precision Screening
Creo/Kodak - Creosettes/Maxtone
Fuji - just since 2004 CoRes screening

More info is available here:
Quality In Print: Halftones and grey levels - part 1 of 2

and here:
Quality In Print: Halftones and grey levels - part 2 of 2


best, gordon p

[Shediac]

Thanks Kevin. When you say hybrid AM screening you mean?

[Kevin@Kodak]

I have to disagree with Kevin on this one.

Shediac is likely concerned about achieving all the grey levels needed for 133 lpi screening on a 1200 dpi device.
The classic formula to determine grey levels is:
(dpi/lpi) squared + 1 = number of grey levels

So for 133 lpi at 1200 dpi:

1200 dpi/133 = 9
9 squared = 91
91 + 1 = only 92 possible tones

However, since about 1985, Supercell screening (a function of the RIP not the output device resolution) has eliminated the grey levels limitation by "dithering" the halftone dots. This type of conventional AM screening is available, if not the standard, from all the vendors - including Kodak.

More info here:

Quality In Print: Halftones and grey levels - part 1 of 2

and here:

Quality In Print: Halftones and grey levels - part 2 of 2


best, gordon p

To get technical, 9 squared is 81.

The point being, we support 200lpi on the device he mentions, so his need for 133 is certainly met. My point about SQUAREspot enabling 200lpi in a robust, consistent manner on a 1200dpi device stands.

Kevin.

[Shediac]

Gordo, now I'm a bit confused. Does this mean we have to purchase different screening technology from Kodak?

[Kevin@Kodak]

Thanks Kevin. When you say hybrid AM screening you mean?

Actually, as Gordon rightly points out, we support normal 200lpi screening on our 1200dpi engine too (using supercell dithering, as he describes). Normally though, for something as high as 200lpi on a cold-set newspaper press and low-grade stock, we would suggest a hybrid screen to improve printability and quality.

Hybrid screens differ in the highlights and shadows from a normal screen. Essentially, at a certain minimum dot size, instead of making the dots smaller we start removing them in an FM-type manner. This gives fewer dots instead of smaller dots - allowing a finer screen overall (especially relevant in mid-tones) while ensuring you can actually print/hold the highlights and shadows.

If you want more detail on hybrid screens, I can send you some. Most vendors offer such an option these days.


EDIT for clarity - you shouldn't need to purchase anything special in addition to the normal screening to print your 133lpi work.


Kevin.

[SteveAgfa]

Ummm... Kevin -
You're sounding like me now!

We first came out with our Sublima XM screening (Hybrid-ish) for newspaper applications.

Regards,

[gordo]

To get technical, 9 squared is 81.

The point being, we support 200lpi on the device he mentions, so his need for 133 is certainly met. My point about SQUAREspot enabling 200lpi in a robust, consistent manner on a 1200dpi device stands.

Kevin.

Thanks Kevin for catching my typo (but I already caught after I posted and had edited accordingly).

Yes you support 200 lpi, now he knows how it's done in the screening engine. I did not speak to SQUAREspot because it did not seem to be relevant to the OP's question.

best, gordon p