[Scribus] Printer.s dots?

[Craig Ringer]

Frank Cox wrote:
> The Bargain Hunter has recently purchased some offset presses and now
> does all of its printing "in-house".
> 
> We print the plates for the presses directly off of a 1200 dpi HP laser
> printer.
> 
> The press operator tells me that we can get better/finer shading if we
> use what he called "printer's dots" though he wasn't sure that was the
> proper name for it.  These are the fine dots that you can see in some
> professional printing jobs as background shading and whatnot, kind of
> like the dots that make up a newspaper photo.

It sounds to me like what he's after is the use of a coarser line screen 
for halftoning. You really need to find out what line screen is best for 
your press, and use that.

If you're printing on a 1200dpi printer, by default it'll use an 
extremely fine line screen for halftoning. It should certainly be 
possible to use a much coarser line screen while retaining really nice 
edges for type. Work used to do that at work when using a 4800dpi laser 
imagesetter - one *NICE* piece of equipment - but it had an external 
software RIP, and I don't really recall where the settings came from. I 
think Quark might've been generating the halftoning directives.

I'm a bit confused as to how you're printing plates on a laser printer, 
though. While I'm very, very far from a press expert, I thought the two 
types of plate in use both required special equipment - UV or Infrared 
platesetters - to produce. Do you mean that you're printing a page that 
you then use to make the plate (like the POST used to do with the 
imagesetter) ? That's the process the POST's printers used to use, 
though the POST supplied the pages for them to turn into plates. For 
several years now they've used CTP equipment where they just send a PDF 
the POST supplies to their RIP, and it drives the platesetter directly. 
No intermediate paper result for the camera required. I saw an immediate 
improvement in results, too, though it's unclear how much of that was 
due to skipping a step in plate production and how much was due to other 
improvements that came along with it.

I might see if I can dig out a few sample PostScript jobs from Quark 
with the POST's old settings and see how the halftoning works.

--
Craig Ringer