QTR-Quadtone RIP

--- In QuadtoneRIP@yahoogroups.com, Paul Roark  wrote:

> To see how adding yet another neutral ink would look, try setting up the Y
> position (your second LC) as follows:  Have the Y curve copied from the LC
> curve; use an ink limit on LC and Y that is half of the current LC ink
> limit.

I have done this to create a new profile to use the same ink in LC and Y.  There seems some improvement, particularly at the darker end of the scale, noticeable when checking shadow detail on Keith Coopers Mesa Verde test image.  However the round thingamajig shows annular (circumferential?) banding, indicating poor transitions. This shows a different distribution of tone to the profile with just one LC.  Also, on a 21 step wedge print there is a vertical line showing, on the top graduated continuous scale, between 30 and 35% there may also be similar artefacts above 70% but my lighting isn't helping to see these.  Using Northlight's Grayscale Linearisation image, I am getting a sharp step from light tones to mid tones at 4 (40%?) and a noticeable step at 8 (80%?).  100% black is also a noticeable "bullseye".

> Basically, the more inks we have firing at a time (within reason) the less
> likely we'll have visible microbanding.

I am getting microbanding throughout an A4 print, which seems less noticeable in the profile with two LCs, however I'm wondering if this is being exacerbated by the paper I'm using.  This has caused a lot of feed issues, I am currently having to clean the loading roller every five or so sheets as paper is loading very poorly.

Would linearising with many more values, eg from a 50 step wedge, improve the tonal scale?

Ross