I have indeed 'noised' my digital images before dithering. This didn't
though take all the smudge away. What I did was that I searched for all
49 50 and 51% dots and changed them ( it's not too difficult in
photoshop, but a bit messy).
>It is important to realize that any 50% dithering problem will occur in
>the 50% area of the *negative*, not the 50% area of the print. First, I
>have an image in Photoshop which I am happy with. To this I apply the
>correction curve to make an appropriate negative. This correction curve
>results in a washed out image on my screen. It is in this washed out
>image that you have to go hunting for the 50% areas (use the info
>palette). If you have dithering problems, they will manifest themselves
>in these areas of your print, EVEN THOUGH these areas (in my case anyway)
>are actually 3/4 tones on the final print. Are these the ares in which
>you have been looking?
>
>David
And I did mean really 50% in the negative.
But in my previous school we designed a screening method we called
NoScreen, to eliminate the mess. What we did was basicly separating every
picture to two tonaly slightly different images which were dithered
and then mounted on top of eachother in the computer (pagemaker)
and printed. Thus the 50% of each pictures were smoothed by a different
tone on the other. It is like duotoning every negative (a lot of work in
a triotone). But it really worked. We've used it only on offset (duo,trio
and CMYK). I'm now taking it to other medias.
And this: don't let the whitest part go to 0, let it be 1. It looks so
much nicer.
_PEKKA NIKRUS__<pnikrus@uiah.fi>________UNIVERSITY OF ART AND DESIGN HELSINKI
http://www.polycon.fi/ART/pekka/ DEPARTMENT OF PHOTOGRAPHY
"Everybody's searching for something they say, I get my kicks on the way"