QTR-Quadtone RIP

Hallo,

you can find a german explanation for custom curves at the following link:

http://www.tauberlin.de/QTRKurven.pdf

Best Regards

Rainer


Am 30.03.2010 12:01, schrieb Matthias Eblen:
>
> Hello Mike,
>
> I am also using the Epson 2880 and I am pleased with the results.
> Up to now I printed mostly wih the ABW mode. Now I want to move into 
> printing with QTR.
>
> As I am new to QTR I ask you for your experience. Did you create 
> specific curves that are not included in QTR? Coming from Germany I 
> mostly use Hahnemuehle papers like Photo Rag, Bamboo and Baryta.
>
> Best regards
> Matthias
>
> -----Ursprüngliche Nachricht-----
> Von: Michael King
> Gesendet: 30.03.2010 10:27:09
> An: QuadtoneRIP@yahoogroups.com <mailto:QuadtoneRIP%40yahoogroups.com>
> Betreff: Re: [QuadtoneRIP] Re: New Release of QuadToneRIP 2.7.0 for 
> both Mac and PC
>
> >I am using 2880 and only 2880. Why use anything else :)
> >Mike
> >
> >On 30 March 2010 06:36, tboleyyh wrote:
> >
> >>
> >>
> >> StudioPrint uses rather severe partitioning, and successfully 
> linearizes 6
> >> and 7 inks. Of course it costs much much more. My only point is 
> that lots of
> >> overlap is not necessary for this, it can be done, and the number 
> of inks is
> >> not the problem.
> >> Also, many of us prefer not to lessen the number of grays, as we 
> don't find
> >> 3 Ks adequate for our particular needs. If you do, kudos, but one 
> of QTR's
> >> great benefits is it's flexibility as a monochrome driver for all 
> kinds of
> >> demanding setups for a variety of needs.
> >> Mike, are you at 1440 or 1880? Variable dot in every, of many, grays
> >> (1440x720) can be very difficult, even only 3. In many of these 
> setups it
> >> works because of heavy light ink limiting, which is likely 
> primarily small
> >> dots...
> >> Tyler
> >>
> >>
> >> --- In QuadtoneRIP@...m 
> <mailto:QuadtoneRIP%40yahoogroups.com> ,
> >> "shileshjani" wrote:
> >> >
> >> > Mike,
> >> >
> >> > I must say I have never ecountered posterization issues with 
> customary
> >> inks that use K, LK, and LLK alone, or as backbone followed by LM, 
> LC, and
> >> others for toning via use of "toner" or "copy curve from" in QTR 
> ink setup.
> >> >
> >> > I think Cone type overlap may (perhaps) be required when using 4+ 
> gray
> >> inks, which in my opinion is at best an overkill, and technical 
> mas@#$%^tion
> >> at worst. I have not seen a print that was better simply because it 
> had 6 or
> >> 7 shades of gray. Try to reduce the number of gray inks in your set 
> up, and
> >> use standard QTR curves design tools. I am curious what your eyes 
> will see.
> >> >
> >> > Shilesh
> >> >
> >> > Shilesh
> >> >
> >> > --- In QuadtoneRIP@yahoogroups.com 
> <mailto:QuadtoneRIP%40yahoogroups.com> ,
> >> Michael King wrote:
> >> > >
> >> > > Roy,
> >> > >
> >> > > >>If you have posterization issues it's almost certainly due to 
> other
> >> > > issues.
> >> > > More bits and more overlap are pretty much the very last things 
> to be
> >> > > concerned about. Posterization is usually in the image or you 
> have bad
> >> inks
> >> > >
> >> > > So all I can say is that I have a image that posterizes with 
> QTR curves
> >> > > (limited overlap) but not Cone style overlapping curves. Same inks,
> >> same
> >> > > printer. Solved the problem by using using overlapping curves and
> >> > > linearizing with my own spreadsheet based linearization tool. 
> This 7
> >> ink set
> >> > > up is using a mix of HP-PK and Eboni MK (18% & 100%). It may 
> have been
> >> > > caused by some other effect that I removed by using overlapping 
> curves,
> >> but
> >> > > there is no doubt that overlapping curves solved the problem, 
> whatever
> >> is
> >> > > causing it.
> >> > >
> >> > > Mike
> >> > >
> >> > >
> >> > >
> >> > >
> >> > > On 29 March 2010 19:00, Roy Harrington wrote:
> >> > >
> >> > > >
> >> > > >
> >> > > > On Mon, Mar 29, 2010 at 9:02 AM, Michael King > 40gmail.com>>
> >> > > > wrote:
> >> > > > >>>Is there any benefit in re-creating custom curves for this new
> >> version?
> >> > > > I
> >> > > > > have just finished profiling two papers for QTR and wonder 
> if they
> >> would
> >> > > > be
> >> > > > > a) compatible, b) have greater accuracy with this new version?
> >> > > > >
> >> > > > > As I read in Roy's answer to my earlier question - there 
> has been
> >> no
> >> > > > change
> >> > > > > to profiling. Its still 8 bit based. BUT he is interpolating
> >> between the
> >> > > > 8
> >> > > > > bit values to generate intermediate values to support 16bit.
> >> > > >
> >> > > > There have always been 256 points in the QTR curves but the 
> values at
> >> each
> >> > > > of the points have always been 16-bit. The 256 points are 
> already way
> >> > > > overkill
> >> > > > compared to, for instance, color ICC profiles. ICC color 
> management
> >> > > > typically
> >> > > > uses interpolation with just 25 points so QTR curves have 10 
> times
> >> that.
> >> > > > Interpolation is a perfectly good technique.
> >> > > >
> >> > > >
> >> > > > >
> >> > > > > To be honest paper coatings are barely consistent enough 
> across the
> >> page
> >> > > > to
> >> > > > > let you profile at 7 bits (128 values) never mind more than 
> 8 bits.
> >> So we
> >> > > > > would be able to gain nothing from Roy directly increasing the
> >> curve
> >> > > > > resolution beyond 8 bits.
> >> > > > >
> >> > > > > You might ask what's the benefit of 16 bit printing ? Well 
> I expect
> >> the
> >> > > > main
> >> > > > > benefit is in helping smooth tonal areas avoid 
> posterization, by
> >> creating
> >> > > > > more ink values in the tonal graduation.
> >> > > >
> >> > > > If you have posterization issues it's almost certainly due to 
> other
> >> issues.
> >> > > > More bits and more overlap are pretty much the very last 
> things to be
> >> > > > concerned about. Posterization is usually in the image or you 
> have
> >> bad
> >> > > > inks.
> >> > > >
> >> > > > Roy
> >> > > >
> >> > > >
> >> > > > >
> >> > > > > I've been wrestling with this issue for the last few months and
> >> have been
> >> > > > > experimenting with Cone style overlapping curves and QTR less
> >> overlapping
> >> > > > > style. There is no doubt more overlap reduces the problem 
> BUT also
> >> for
> >> > > > some
> >> > > > > papers overlapping curves reduces dmax. So as usual there is no
> >> free
> >> > > > lunch.
> >> > > > > I am excited about the potential of 16 bit printing to 
> address this
> >> issue
> >> > > > -
> >> > > > > just got to Hackintosh my PC first :)
> >> > > > >
> >> > > > > Mike
> >> > > > >
> >> > > >
> >> > > >
> >> > > >
> >> > >
> >> > >
> >> > > [Non-text portions of this message have been removed]
> >> > >
> >> >
> >>
> >>
> >>
> >
> >
> >[Non-text portions of this message have been removed]
> >
> >
> >
> >------------------------------------
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