Digital BW, The Print

Hi Brooks,

I asked that question about the screen-printing process. I am very familiar
with halftone printing/ offset press as my covers are printed that way 5
times a year. I have never heard it referred to as screen-printing process,
I guess that has to do with the screen .. <g> line frequency et al.

>> Can you tell me what the screen-printing process is?
> 
> Screen-printing is another (relatively unused) term for half-tone
> printing. This is the basic method of printing used in almost all
> printed materials these days - newspapers, books, magazines. In
> essence the tones are created by arranging tiny dots in regular rows
> and columns on a page. The smaller the rows and columns (think graph
> paper here) the finer the line screen. Regardless of the size of the
> line-screen, the more a dot fills its little square area (really its
> usually round or oval, but let's not get too technical) the darker
> the area of the image.
> Therefore, a 200 line screen contains 200 dots per lineal inch left
> to right and also 200 dots per inch top to bottom. For reference,
> daily newspapers usually print about 85 lines per inch. USA Today
> prints at 100 lines per inch. Magazines are usually 133-150 lines per
> inch. LensWork prints at 200 lines per inch. And the very best
> photography books out there are at 300 lines per inch. This is the
> functional limit of printing presses. Our LensWork Special Editions
> use an even higher screen - 425-lines per inch. Image setters can
> create this film, but printing presses can't print it so most people
> in the industry are not aware that their image setter will go that
> high!

My cover images are imaged at 200lpi and printed to a sheetfed press. So you
are saying that you are using a screen at 425lpi going to a 200lpi press?
What resolution is required for your imaging to the film?

> Finally, a 425-line screen will represent highlight areas with a 1%
> dot. That means the smallest dots in the finest highlights will be
> 0.0000235 inches in diameter. This is far finer than the size of a
> stochastic dot, and that is why we don't use Dan Burkholder's method
> of stochasitic screening for printing on gelatin silver.

When you refer to stochastic dot, are you referring to stochastic screening
process that eliminates the rosette patterns as it is rather random like an
ink jet?  I have not had the pleasure of using a stochastic screening method
for the image setter and imagined it to be less of a dot and more of a bunch
of threads if you will.

Please tell me, can you see the rosette patterns in your magazine?  I was
always under the impression that if you could not see the patterns then
stochastic screening was used to produce the plates.

> Does this help? I am new to this forum, so I apologize if this is all
> old news to all of you.

All good information is well rec'd.  I will go out and find your publication
today. 

Thanks!  Carolyn