Digital BW, The Print

I am scheming on doing a small promo piece that's very large, 
and very cheap. I'm outputting a digital file directly to this giant 
"xerox machine" that's used for copying blueprints. Page size will 
be about 24x36". It's like a very low-tech 
magazine/diary/travelogue thing.

Question: I sent a file to it yesterday that started with a tiff file 
greyscale, converted to Bitmap, and "Diffusion" type. The screen 
representation of diffusion seemed much tighter dots than the 
Halftone choice. But today when I saw the proof, the 
shortcomings of the machine showed through -- there were 
these "toner line" inconsistencies. My thought is that if I could 
"coarse up" the line screen, it might compensate for the toner 
lines.

Does anyone know what effect changing those Halftone settings 
has? Does anyone know the roughest possible setting?

Thanks in advance.

When you output a file to offset printing the film/press/printer dictates
the screen frequency etc. You can specify a shape (although I've never done
this) but in this case I'm wondering if you shouldn't "coarsen up the line
screen" by using a texture or adding noise to your file and not changing it
to bit map at all.  If you do it this way the "coarsening" effect can be
more random and may hide the toner lines better.

The halftone settings give you a very patterned effect and I doubt that it
would hide any linear flaws from output.

The halftone settings in the bitmap palette will allow you to change the
shape and frequency of the bitmap screen but I only know of artists using
this for special effects, not for going to press. Use a very high frequency
(keeping in mind this is for effect not for actual an actual press output)
and try the round pattern. The file size will dictate the amount of
frequency req'd for the effect you want. Try between 500 and 900, try
changing the angle...

Just a thought,
Carolyn

> I am scheming on doing a small promo piece that's very large,
> and very cheap. I'm outputting a digital file directly to this giant
> "xerox machine" that's used for copying blueprints. Page size will
> be about 24x36". It's like a very low-tech
> magazine/diary/travelogue thing.
> 
> Question: I sent a file to it yesterday that started with a tiff file
> greyscale, converted to Bitmap, and "Diffusion" type. The screen
> representation of diffusion seemed much tighter dots than the
> Halftone choice. But today when I saw the proof, the
> shortcomings of the machine showed through -- there were
> these "toner line" inconsistencies. My thought is that if I could
> "coarse up" the line screen, it might compensate for the toner
> lines.
> 
> Does anyone know what effect changing those Halftone settings
> has? Does anyone know the roughest possible setting?
> 
> Thanks in advance.

Mark,

I believe Dan Margulis' Color Theory list could be very helpful -- lots of
people who know their dots:

Post message:    colortheory@yahoogroups.com
Subscribe:     colortheory-subscribe@yahoogroups.com

Todd

> I am scheming on doing a small promo piece that's very large,
> and very cheap. I'm outputting a digital file directly to this giant
> "xerox machine" that's used for copying blueprints. Page size will
> be about 24x36". It's like a very low-tech
> magazine/diary/travelogue thing.
> 
> Question: I sent a file to it yesterday that started with a tiff file
> greyscale, converted to Bitmap, and "Diffusion" type. The screen
> representation of diffusion seemed much tighter dots than the
> Halftone choice. But today when I saw the proof, the
> shortcomings of the machine showed through -- there were
> these "toner line" inconsistencies. My thought is that if I could
> "coarse up" the line screen, it might compensate for the toner
> lines.
> 
> Does anyone know what effect changing those Halftone settings
> has? Does anyone know the roughest possible setting?
> 
> Thanks in advance.