QTR-Quadtone RIP

Scott,

I did something similar for the 2400 with K7 inks.  Very easy to make profiles for new 
papers using the generic curve descriptor file I made.  Just measure new K ink limit and 
re-linearize.  No need to partition the inks.  I have the ink descriptor file (txt file for Mac) if 
anyone wants to try it.

Carl
 
--- In QuadtoneRIP@yahoogroups.com, "Scott Schroeder" <schrochem@...> wrote:
>
> Howard's approach intriqued me so I gave it a shot from another way. I used
> the 'load curve' option but pasted in 50 points for each ink. I did this for
> the 2200 K7-2880-Hanphotorag profile. I uploaded the qidf to the files
> section under curves/2100-2200 and it's called k7-test.qidf.  I hope that is
> alright with Jon and/or Roy. If not feel free to take it down.
> By visually comparing the curves they look the same. I would be interested
> in your remark about 'flat spots' Roy and see if this would apply to this
> qidf?  The cone curves use up to 255 points but the qtr interface only
> allows for 50 so I chose an equal distribution throughout to maintain
> integrity. The K only has 46 points so it should be a direct match, but an
> ink like Magenta had 254 so it has only 1/5th the points. But I would think
> 50 points would still be enough to prevent any flat spots.
> 
> Scott
> 
> 
> On 1/16/07, Roy Harrington <roy@...> wrote:
> >
> >   Hi Carl,
> >
> > It's easy to do on the Mac, too. Just use:
> > CURVE_K=k7_black.acv
> > CURVE_LM=k7_ltmagenta.acv
> > etc...
> >
> > Howard's idea is an interesting possibility. You could design the
> > basic curve
> > shapes this way and then linearize the result. The potential
> > difficulty would be
> > that you get some flat spots or extra wiggles in the density curve.
> > Just because
> > the look smooth doesn't mean the sum on the curves with different inks
> > would
> > also look that smooth. The linearize can fix only so much. In the
> > specific example
> > it probably would work well since they are designed from existing
> > "good" profiles.
> >
> > Since the K7 inks are so close in density you can have the very large
> > overlaps
> > -- ie. 5 inks instead of just 3. There is also some benefit in the
> > 2880dpi because its
> > only one dotsize. At 1440 there will be 2 or 3 dotsizes used which
> > results in more
> > transitions.
> >
> > For anyone wanting to customize their own K7 ink profiles a very nice
> > approach is
> > to take advantage of the piezo k7 profiles and then build ICC profiles
> > on top of
> > them. This way you get full color management from screen to print with
> > softproofing
> > as well.
> >
> > Roy
> >
> >
> > On Tuesday, January 16, 2007, at 03:14 PM, Carl Schofield wrote:
> >
> > > I assume this is only for the PC version or is there a way to use
> > > the .acv curves with the Mac version of QTR?
> > >
> > > Carl
> > >
> > > On Jan 16, 2007, at 5:44 PM, Howard Shaw wrote:
> > >
> > >> Joost
> > >>
> > >> If you have a look at the Cone-made k7 curves (the 2880dpi ones) they
> > >> are differently constructed to the type of curves that qtr makes.
> > >>
> > >> I've made a web page showing the difference and also how the Load
> > >> curves
> > >> facility in qtr can be used to emulate the type of curves produced by
> > >> Cone's proprietary method.
> > >>
> > >> http://www.howardshaw.org/docs/k7-qtr/k7curves.htm
> > >>
> > >> The main difference is that the normal qtr curve creation method using
> > >> density boundaries usually only allows 3 inks to overlap at a time
> > >> whereas the Cone curves have upto 5 overlapping inks. On the basis
> > >> that
> > >> the more jets firing the better this should lead to a smoother print.
> > >>
> > >> Note that I do not have the K7 inks so this is a technical exercise
> > >> only.
> > >>
> > >> Howard
> > >>
> > >> Joost Horsten wrote:
> > >>> --- In QuadtoneRIP@yahoogroups.com <QuadtoneRIP%40yahoogroups.com>,
> > "Scott Schroeder" <schrochem@>
> > >>> wrote:
> > >>>
> > >>>> I didn't mean you couldn't make curves. I was just saying you can't
> > >>>> make curves that have the nice transitions and crossovers that are
> > >>> in
> > >>>> the supplied curves.
> > >>>> This message will explain it better:
> > >>>> http://tech.groups.yahoo.com/group/QuadtoneRIP/message/1165
> > >>>
> > >>> Thanks Scott, that explains your remarks indeed. But for my
> > >>> information: does it make in practice REALLY any difference whether
> > >>> you use these original PiezoBW curves in stead of making your own
> > >>> curves with QTR? Since I'm printing on 2880 dpi with QTR/2100/UT3D
> > >>> I've a hard time to find any grain in my prints. So, imho on that
> > >>> aspect I expect there is little left to improve by going to 7 inks.
> > >>> But even if so, do the details of the curve then still make a
> > >>> difference on top of that? Or does the claimed smoothness of the NK7
> > >>> inks ONLY appear with the custom PiezoBW curves?
> > >>>
> > >>> Joost
> > >>>
> > >
> > >
> > -
> > Roy Harrington
> > roy@... <roy%40harrington.com>
> > Black & White Photo Gallery
> > http://www.harrington.com
> >
> >  
> >
> 
> 
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