🚀 go-pugleaf

In article <1992Dec17.161309.10151@ircam.fr>, francis@ircam.fr (Joseph Francis) writes:
> I have some questions for desktop gurus. I have been working with
> photographs for some time, and it is still a complete mystery to my
> how to balance the image digitally so the halftone output is of a 
> high quality for offset printing.
> 
...
> My third try now is that I rebalanced the image for a maximum black
> saturation of 85% and minimum of 10%. This doesn't look too bad on
> screen, though it just seems low contrast (obviously). The image still
> seems dark to me, but that relates to yet another problem. I'll be
> getting the linotron transparencies this evening (2540 dpi, ~150lpi
> screen).
> 
> The yet another problem is viewing the data. I can view the images
> with 4 or five separate programs, all of which provide radically
> different interpretations of what is seen, much less how it prints.
> (1) Corel Draw preview displays a dark image.
> (2) PhotoStyler displays a perfect image
> (3) HP Scanjet scanning software displays a perfect image.
> (4) Halo Imager displays a quite dark image
> (5) PageMaker displays a darkish image
> 
> These all describe images which were originally printed quite dark.
> 
> (1) Corel Draw preview displays a darkish image
> (2) PhotoStyler displays a pale image
> (3) HP Scanjet scanning software displays a low-contrast image
> (4) Halo Imager displays a perfect image
> (5) Pagemaker displays a low-contrast image.
> 

You will have to 'calibrate' your printer. The final print needs just a trace of
ink in the highlights, and not quite 100% in the shadows. To get this you USUALY
need a fine dot in the halftone hilights, and a small white 'dot' in the darkest
areas. Include a gray scale and go off that. Examine the PIXELS in the data
with a 'magnifier', or use a real loupe on the film. Then adjust for the effects
you printer introduces. He will probably be able to tell you about the corrections
you need for his press. Note that if you change ink, paper, press, plate type,
Phase of moon etc you get to do it ALL again...

Why are you outputing 300dpi files BTW? Why not full 2400?

~Paul