QTR-Quadtone RIP

this may be a clog. 

i've just encountered this on my 21-step-random print. the banding (or more like pin 
strips) appear in the 30, 45, 20, 35, 50, 25, and 40 patches. i ran the head cleaning cycle 
and it took care of it. perhaps it's the same with yours.

--- In QuadtoneRIP@yahoogroups.com, "Mike Dawson" <dawsonm@...> wrote:
>
> I have started the process of creating a profile for the Cone K6 inks 
> on Epson Velvet Fine Art using an Epson 1280 printer.  I am getting a 
> bit stumped at the point where you print out the 21-step wedge in 
> order to linearize the curve.  The issue is that the step wedge has 
> fairly obvious banding at densities above 65%.  This seems like it 
> would be an issue when trying to take accurate density readings 
> (using my ColorVision Spectro 1005).
> 
> Can anyone give me some common causes of banding in the step wedge?  
> I'm assuming it is due to poor data plugged in from ink separation 
> test prints.  But I'm hoping others can clue me in to what 
> specifically may be the cause of the banding.
> 
> With the 1280/K6/Epson VFA combination I found that the ink limit for 
> the Black ink was at 80%.  The density shoulder actually begins 
> occuring at about 50% with a density of 1.62.  It hits 1.69 at 80% 
> and holds that value up until 100%.
> 
> I then printed out the ink separation test using an ink limit of 
> 85%.  I then determined the densities (compared to Black) of all the 
> other inks from the 100% squares.
> 
> I also measured all ink patches from the first ink separation test.  
> Based on advice from Paul Roarke I used the ink limits from these 
> measurements to plug into the curve creation windows.  I found that 
> ALL of the inks (except for Black) had no plateau and were increasing 
> in density all the way up to 100%.  So I plugged in 100% ink limit 
> for all the inks, except for Black which has the default of 80%.  
> Black Boost was left blank.
> 
> Any help here?
> 
> Mike
>