Digital BW, The Print

> From: Ernst Dinkla <E.Dinkla@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Thu, 12 Jan 2006 09:44:54 +0100
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: Re: [Digital BW] Re: QuadTone RIP vs Epson inks
> 
> Steve Kale wrote:
> 
>> The figures quoted above are
>> from the calibration page printed at 100% ink limit and reading the 55%, 40%
>> and 80% patches, ie in creating a QTR curve one would likely limit K on HPR
>> to at least 55%.  If I recall correctly, this is a lot lower than what I
>> used to use with the MIS UCs or Epson Ucs - I guess that would save some
>> ink.  
> 
> Steve,
> 
> I should wait for the extended report but:
> 
> The limitation on 55% is because your Dmax is reached there
> and no increase above ?  What about detail above that patch, does it still
hold ?

Re density - pretty much yes.  Interestingly, on the calibration printout
all the black text is printed at 100% and while not a bleed test like the
chart you prepared there is no discernible bleed issue.  The text is tack
sharp at 1440dpi.  If I were making QTR curves for these inks I would cut K
at 55% on HPR (40% on EPSG and 80% on EAM) or below (with perhaps boost to
these limits) and run the LK ink much higher.


> A more theoretical question, if an ink reaches Dmax at 55%
> isn't that an unbalanced distribution on that particular
> printer ?  In other words aren't you cutting off one droplet
> size etc ? This is for the black, it could be good for color
> saturation though. If the inks behave more like dyes one
> wouldn't expect a Dmax limitation that low.

The other inks can run higher in load and still show increasing density.
Using QTR's calibration page is quite useful in this respect but of course
the results are RIP dependent.  For colour I am simply interested in the
Epson driver results as I while I might be able to afford John Edmunds'
PocketRIP I can't afford an n-space profiling package.  So I'm stuck with
Epson's ink limits and linearization.  On the TC918 target I used for colour
profiling, the 0,0,0 patch returned Lab 10.8, 1.0, -1.7 on HPR.  My concern,
of course, is that the Epson ink load is totally inappropriate for this ink.
Figuring that out will require a lot more testing.