QTR-Quadtone RIP

There was some discussion of this in the past few months. I'm not sure if it
was on this list or the BW printing list. The most active participant was
Steve Kale. The essence of it was to print several inkseparation pages each
limited for the particular grey or toner ink in question. The goal was to
use each ink (grey or toner) to its fullest in order to minimize dots in the
transitions. I don't recall the procedure in detail and don't do it myself.
I also have not seen any comments on the results of this approach. 

More comments below...

> -----Original Message-----
> From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com] On
> Behalf Of Jamie Creed

...snip...

> 
> the initial overall Ink limit of 80% was chosen because the black
> ink maxed out at 80%, however non of the other inks maxed out on the
> initial 100% ink separation printout. So when I produce my second
> Ink separation page (in calibration mode) with the Ink limit slider
> set to 80%, the black ink is printed as one would expect (with a nice
> gradual increase in density, until it max's out at 100,) however,
> because I have set the ink limit to 80%, all the other inks printout
> with a reduced density when their individual densities where fine
> with the initial 100% Ink separation page.
> 
> So should I set the default ink limit in QTR curve creation to 100%
> (so all the other inks are at their max,) and set the Black ink
> limit to 80% as established above.

If you set the default ink limit to 80, you can always set the limit of any
individual ink (toner or grey) to a different limit - larger or smaller than
the default. Or, you can do what you suggest. In the end you need to be able
to tell QTR what the density of each ink is as a percentage of black at its
limit.

The consequence of setting too low a limit (by a few percentage points) is
not that great (IMHO). The curve can still be linearized. You might see a
few more dots in the transitions but I'm not convinced and haven't seen any
results. There will still be transitions with dots, just at a slightly
higher density.

> 
> Hope somebody understands what I'm getting at, and I would like to
> hear if anybody builds curves with this approach, or does everbody
> follow Tom Moore's excellent user guide procedure, which sets the
> overall hardware ink limit to all inks (if I understand it
> correctly,)

Well the guide might not be as excellent as you state if it implies that you
set the overall ink limit to all inks. There are many reasons that one might
have for setting a limit other than the default. The default limit is
basically a convenience.

> 
> regards,
> 
> Jamie Creed
> 


Tom Moore