Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Daniel Staver" 
<daniel@p...> wrote:
> > The compression probably messes up some of the transitions 
> > but I think the main thing you are seeing with the vertical 
> > lines is just the individual 256 steps of gray.  Photoshop 
> > will create two kinds of gradients -- 256 hard edged steps 
> > and smooth dithered gradients.  The "dither" option in the 
> > Gradient tool there a check box for the two kinds.
> 
> I think there are more problems than just the individual steps
> showing... Here I've increased the contrast on the stepwedge to make the
> problem more visible, then enlarged it quite a bit:
> http://daniel.staver.no/img/compressedstepwedge.jpg
>  
> > It's real easy to fix up the 21step.  Just select the top 
> > half and make a new gradient with dither on.  Select the 
> > bottom half, make a gradient with the dither off, and 
> > posterize to 21 levels.
> 
> I made a new cleaned-up version without artifacts and updated the
> technical.psd file with the new stepwedge. I also made a smaller version
> of for test prints. All three files are available here:
> 
> http://download.petraflux.com/technical.zip (3.59mb)
> 
> --
> Daniel Staver
> http://daniel.staver.no

Much nicer, Daniel.  One thing I noticed however is that two of the
files, the smaller wedge and technical, are Adobe RGB rather than
Grayscale.  This introduces some profile conversion differences
especially in the 95% step -- it comes out 96% with a dither.

Roy