Re: grayscale settings for offset printing
Re: grayscale settings for offset printing
- Subject: Re: grayscale settings for offset printing
- From: Roy Harrington <email@hidden>
- Date: Sat, 17 Dec 2005 12:29:06 -0800
There are several issues that can be problems when you go to lots of
steps.
Consider a 101 stepwedge using a standard 8 bit grayscale. The gray
values
are actually 0-255 and creating K values in Photoshop will result in
some
steps being 2 units and some being 3 units which is a pretty big
variation.
A 21 step gives 12s and 13s which are probably just fine. There are
two solutions
to this -- pick all 3 units steps which is 86 steps or all 5 units
which is 52 steps.
You can also design a wedge in 16 bit mode -- its tricky to get the
exact values
but I think Posterize works correctly. The wedge can then be converted
to 8 bit
and Photoshop with dither the intermediate values so they are still
evenly spaced.
The second issue is more insidious. There's a fair amount randomness
in patch
density due to the way inkjet printing works. This density noise is
less than visible
to the eye but with the precision of spectrophotometers I think you can
pick this up.
This can end up introducing artificial noise into your prints and
soft-proofs
by having a noisy transfer curve.
Roy
On Saturday, December 17, 2005, at 11:10 AM, Roger Breton wrote:
I have made my own for 101 patches. Hope that helps.
Gee, Steve, have you found that going to 101 from 51 helps a lot?
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
-
Roy Harrington
email@hidden
Black & White Photo Gallery
http://www.harrington.com
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