Digital BW, The Print

Yes, Mike, the potential issue is just with respect to the Epson driver and the k3 printers. The problem related to my attempt at an easier sequential mixing for the first iteration of Carbon-6.  It turned out to be a mistake for the k3's -- 33% too strong relative ot the 16.5% LK (M).  I think the K3s are OK with the standard 100, 30, 18, 9, 6, 2% mix, where LK = 18%, but I just don't have good enough notes to be sure.

With QTR you can mix and control any reasonable blend.

I do, however, try to keep my mixes uniform and as Epson driver compatible as possible, so that profiles can be shared and novices can get up and running more quickly.

Paul
www.PaulRoark.com 


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Michael King <drmrking@...> wrote:
>
> Paul,
> 
> Just to be clear when you describe the following issue - that's using the
> Epson driver - correct ? Txs Mike
> 
> >>There is at least one possibly open issue with respect to the recommended
> Eboni-6 ratios in K3 printers. With the original Carb-6 mix, the C-position
> was 33%, then the M/LK was 16.5%. If no PS curve was used to partition the
> inks, there was some posterization in the deep shadows. The high gray
> substitution of the K3 printers with an input of an R=G=B grayscale file
> caused the relatively lighter, original Carb-6 16% LK to be too light
> relative to the darker 33% C-position ink. I believe this is not a problem
> with the standard Eboni/Carbon-6 setup (using 18% for LK and 30% for C), but
> it's something to keep an eye on. If it is a problem, then the LK needs to
> be the 30% ink, not the 18% ink
> 
> On 10 March 2011 17:05, Paul <roark.paul@...> wrote:
> 
> >
> >
> > "Gerd" <lichtwert@> wrote:
> > >
> > > ...
> >
> > > what are the specific/explicit dilutions for a carbon-6 mixing for an
> > eight-color printer like the R2880? I would appreciate a detailed listing
> > for each color related to volume.
> >
> > I have never actually set up a 2880. Even with my 7800 I have non-Eboni
> > inks in 3 positions. So, the "perfect" setup for an 8-ink printer involves
> > some uncertainty. However, start with what I recommend in the PDFs on the
> > subject.
> >
> > Michael King <drmrking@> wrote:
> > >
> > > ...
> >
> > > If you are making your own profile doesn't matter which
> > > dilution goes in which channel.
> >
> > This is true if one makes QuadToneRip profiles. This is what I use to print
> > with my 7800.
> >
> > However, I most often like to set up a printer with an ink arrangement that
> > is compatible with the Epson driver. I think this lowers the entry barriers
> > for new users. If they can load the inkset, hit the Print button in PS and
> > get an OK print, the positive feedback avoids a lot of headaches (both for
> > them and me).
> >
> > So, to get down the learning curve with the least amount of pain, I
> > recommend new people start with an inkset that is compatible with the Epson
> > driver, then learn simple linearization so that QTR's Create ICC-RGB can be
> > used to make ICCs, and finally, learn the full QTR rip approach, which
> > allows one freedom from the Epson driver constraints.
> >
> > Back to step one -- the Epson driver compatible Eboni-6 arrangement for an
> > Epson k3 class printer: page 2 of
> > http://www.paulroark.com/BW-Info/Eboni-6.pdf has the recommended setup.
> >
> > For Carbon-6 I recommend the same mixing ratios as for Eboni-6. See
> > http://www.paulroark.com/BW-Info/Carbon-6.pdf
> >
> > Note that I initially used a different mixing ratio for Carbon-6 to
> > facilitate mixing with no scales. This ran into several problems. Stick to
> > the 100, 30, 18, 9, 6, 2% standard Eboni/Carbon-6 ratios. Once the base is
> > mixed the specific gravities are close enough to use the same ratios for
> > both volume and weight mixing.
> >
> > For the base, the only ingredient you need to adjust for is the glycerol --
> > heavy at a specific gravity of about 1.26. So, the volume would be the
> > weight percentage divided by this, with water being the remainder -- taking
> > up the amount of the difference.
> >
> > There is at least one possibly open issue with respect to the recommended
> > Eboni-6 ratios in K3 printers. With the original Carb-6 mix, the C-position
> > was 33%, then the M/LK was 16.5%. If no PS curve was used to partition the
> > inks, there was some posterization in the deep shadows. The high gray
> > substitution of the K3 printers with an input of an R=G=B grayscale file
> > caused the relatively lighter, original Carb-6 16% LK to be too light
> > relative to the darker 33% C-position ink. I believe this is not a problem
> > with the standard Eboni/Carbon-6 setup (using 18% for LK and 30% for C), but
> > it's something to keep an eye on. If it is a problem, then the LK needs to
> > be the 30% ink, not the 18% ink.
> >
> > Hope this helps.
> >
> > Paul
> > www.PaulRoark.com
> >
> >  
> >
> 
> 
> [Non-text portions of this message have been removed]
>