Digital BW, The Print

I have just finished creating a nice smooth QTR curve for EEM paper for my new Epson 1400.  There are however two issues that I would like to clarify before moving on to creating custom curves for more expensive fine art papers (Hot Press Natural, Photo Rag, Velvet Fine Art etc...).  The solution to both my issues might be interrelated which is why I am putting them in the same post.  But first to the equipment that I am using:  New Epson 1400 bought last week at BHphoto, New sets (2)of refillable MIS cartridges (bought last week), Set of 4oz MIS EB6 inks (bought last week), Colormunki spectrophotometer (LAB values for curve creation), QTR 2.7.0.0 (two 2.7.0.1 patched files that fixed "Calibration Chart" glitches), Windows XP SP3.  Ink carts were filled, primed(EB6 inks),and installed in virgin EPSON 1400 by me about 3 days ago.  All nozzles seem to be firing well.  Only had one misfiring nozzle(Magenta) on the morning of my second day after installation of the new inks.  One cleaning cycle took care of that and I have only had 100% good results on "Nozzle Check" since.  I get very smooth prints on EEM using my custom "EB5" curve (see below why I left out Light Cyan to create my curve).  No microbanding, no density shifts in smooth areas such as the sky, no "inkjet marks" in the direction of the printhead movement whatsoever WHEN USING A FULL SET OF INK.  

Issue #1:  When printing Black Only (using the MIS EEM-BO curve that comes standard with the QTR profiles) I get density shifts that are noticeable in smooth sky sections.  These are basically stripes (1/2 inch wide along the direction of the printhead movement) with slight but regular shifts in density.  These stripes are gone when using the full set of ink by using my "EB5" curve described below.  

Issue #2:  When printing the 100% and 35% calibration chart I noticed that there is not much difference in the density of Light Cyan and Light Magenta.  I thus left out Light Cyan when creating my curve since it printed warmer than Light Magenta (LAB B values were consistently higher on EEM paper).  The strange thing is that in my Epson 1400 printer and when printing out the second calibration chart (@ 35%), the max density of my Light Magenta was slightly higher than that of my Light Cyan (L=57.8 for LM vs L=62.7 for LC).  Again this is at the 35% ink limit for both.  According to Paul Roarks PDF the LC solution should be a stronger mix.  So I looked at the 100% calibration chart (the first one).  There both LM and LC seem to max out at about the same density (perhaps a reasonable compromise to make printing with the EPSON driver simple for those that choose that route).  So it seems that their (LM and LC) Eboni mixtures are very close.  It also seems that my 1400's default density gradient for the LM nozzles is steeper than for the LC.  Is this how the 1400 is designed or is my MIS LC cartridge causing too much back pressure?

As for a solution to my BO problem, I was thinking of sacrificing the LC from my EB6 mix and replacing it with a second 100% Eboni mix.  This second K might help in getting better BO prints by statistically averaging out nozzle inconsistencies in my BO prints.  Would this be a viable alternative or should I get to the root of my BO problem.  If so what could be a solution to my stripes in my BO prints?  Another advantage of keeping the standard LC dilution is that it will make those google map directions look much nicer when printing through the standard epson driver :-)

I know I am throwing out a lot of info in just one posting but it all seems interconnected.  any input would be much appreciated!!!!

"Yan" <ylucille@...> wrote:
>
> ... new Epson 1400.  ... EB6 inks ...
> 
> Issue #1:  When printing Black Only (using the MIS EEM-BO curve that comes standard with the QTR profiles) I get density shifts that are noticeable in smooth sky sections. ...

I noticed the same thing printing glossy black only.  With my small images on brochures and high contrast images it didn't show up, but for many images I don't think black only is up to the job.
 
 
> Issue #2:  When printing the 100% and 35% calibration chart I noticed that there is not much difference in the density of Light Cyan and Light Magenta. 

LC = 9% Eboni, LM = 6% Eboni.

One way to profile that I like involves using some of the gray inks as "toners" to give more inks firing at the same time.  Just split the ink limit between the gray channel and the toner channel.

> I thus left out Light Cyan when creating my curve since it printed warmer than Light Magenta (LAB B values were consistently higher on EEM paper). 

The peak of warmth is the M 18% ink, though this may depend on the paper.  Usually the K and Y (2%) are the most neutral.  One thing to consider is to make a profile with just the Y and K and then use the sliders to use that and a full inkset profile together, varying the percentages depending on the importance of smoothness v. neutrality. As a target, on Epson Hot Press your paper white to maximum Lab B can be as low as 1.4 units.

> The strange thing is that in my Epson 1400 printer and when printing out the second calibration chart (@ 35%), the max density of my Light Magenta was slightly higher than that of my Light Cyan (L=57.8 for LM vs L=62.7 for LC).

I wonder if that inkset is mixed correctly.  I found an old Eb6 calibration print for Epson Hot Press, and at 35% the LC Lab L = 39, the LM Lab L = 51.


>... seems that my 1400's default density gradient for the LM nozzles is steeper than for the LC. 

My impression has been that all the jets/channels are the same.  That is, when the same ink is fired out at the same level, the resulting density is the same.  For example, a black only profile for K will work if the K ink is put in the C channel and the profile just switched around.

 
> ... averaging out nozzle inconsistencies in my BO prints.  ...


Using more than one channel of K can work.  I used that for the 1800 "3-MK" approach.  Start one channel at a time to get smoother highlights. 

Good luck with the system.

Paul
www.PaulRoark.com

> I wonder if that inkset is mixed correctly.  I found an old Eb6 calibration print for Epson Hot Press, and at 35% the LC Lab L = 39, the LM Lab L = 51.

Thanks for those values. I now believe I have found the problem.  I just printed a '100% Calibration' sheet of my EB6 inkset for Epson Hot Press.  At 35%, my LC Lab L=63.  Way off!  LM @35% is L=59.6.  I think your suspicion was correct.  My LC mix is off.  What seems to agree with that hypothesis is that the LC ink is the warmest.  Warmer even than the Magenta ink.  the LC @35% has a LAB B value of 6.7. My LM @35 has a LAB B value of 4.  Huge difference!  I actually dont need a spectrophotometer to see this.  The LC patches look distinctly brown compared to the more neutral appearance of the LM pathces.  To compare to the Magenta warmth I used the 10% patch because it has the closest Lab L value.  For 10% M the Lab B value is 5.7.  
All of this is very telling of what might have happened.  I believe that my 4oz LC bottle was filled from an LC reservoir that was not mixed frequently enough to counter the settlement of the carbon particles.  This would explain both the low density and the high warmth of my sample.  The larger/heavier carbon particles settle at a higher rate thus leaving the smaller (and warmer) particles on top.  
wow..all this is starting to remind me of my days as a physics undergrad working with centrifuges and carbon nanotubes...

"Yan" <ylucille@...> wrote:
>
> 
> >  I found an old Eb6 calibration print for Epson Hot Press, and at 35% the LC Lab L = 39, the LM Lab L = 51.

This morning the full Lab reads for Eb6 & Epson HPn, at the 35% patch of the 100% QTR calibration print, are as follows:

LC = 39, 1.3, 2.3 (plus or minus close to 0.2 for the Lab b)

LM = 50.5, 1.8, 3.5  (")


> 
> ...  At 35%, my LC Lab L=63.  Way off! ...

>... the LC ink is the warmest. 

While the above reads make it look like the LM is warmer, where the LM has a Lab L = 39, it's B = 2.1

>  the LC @35% has a LAB B value of 6.7. My LM @35 has a LAB B value of 4.  Huge difference! 

If this is on Epson HPn, I wonder if this is Eboni-based in at all.  

  
> ... I believe that my 4oz LC bottle was filled from an LC reservoir that was not mixed frequently enough to counter the settlement of the carbon particles. ...

When I toured the MIS facility a number of years ago, that was my main criticism of the way they handled inks.  There was no mixing or agitation of the large pigment containers out of which they filled small bottles and, indirectly, I assume, carts.  If MIS is not agitating its Eboni-6 tanks, that could be a problem.

I use Eboni-6 in my 1400, but I don't buy it from MIS.  I have a gallon of the Eboni-6 base that I was able to get from Zeiss a couple of years ago.  So, I mix and QC my own.  That may be a major advantage of Carbon-6 if what we are seeing is MIS QC problems.  I'll notify MIS of the issue.


> wow..all this is starting to remind me of my days as a physics undergrad working with centrifuges and carbon nanotubes...

Did you notice the article recently that carbon nanotubes made the blackest object (print?) yet?  They're still a bit expensive for our uses in B&W, however.

Paul
www.PaulRoark.com

Had not read the article on nanotubes being so efficient at absorbing waves/particles in the visible spectrum :-)

Thanks for getting back to me about my ink mixture issues.  I'll send you an excel file later today with all the LAB values (L, A, and B)of all six inks when printing them in the 100% calibration mode on EpsonHotPressNatural. Hopefully this kind of an organized reference might be of help to MIS should they be interested in troubleshooting.  
Yan

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul" <roark.paul@...> wrote:

>
> "Yan" <ylucille@> wrote:
> >
> > 
> > >  I found an old Eb6 calibration print for Epson Hot Press, and at 35% the LC Lab L = 39, the LM Lab L = 51.
> 
> This morning the full Lab reads for Eb6 & Epson HPn, at the 35% patch of the 100% QTR calibration print, are as follows:
> 
> LC = 39, 1.3, 2.3 (plus or minus close to 0.2 for the Lab b)
> 
> LM = 50.5, 1.8, 3.5  (")
> 
> 
> > 
> > ...  At 35%, my LC Lab L=63.  Way off! ...
> 
> >... the LC ink is the warmest. 
> 
> While the above reads make it look like the LM is warmer, where the LM has a Lab L = 39, it's B = 2.1
> 
> >  the LC @35% has a LAB B value of 6.7. My LM @35 has a LAB B value of 4.  Huge difference! 
> 
> If this is on Epson HPn, I wonder if this is Eboni-based in at all.  
> 
>   
> > ... I believe that my 4oz LC bottle was filled from an LC reservoir that was not mixed frequently enough to counter the settlement of the carbon particles. ...
> 
> When I toured the MIS facility a number of years ago, that was my main criticism of the way they handled inks.  There was no mixing or agitation of the large pigment containers out of which they filled small bottles and, indirectly, I assume, carts.  If MIS is not agitating its Eboni-6 tanks, that could be a problem.
> 
> I use Eboni-6 in my 1400, but I don't buy it from MIS.  I have a gallon of the Eboni-6 base that I was able to get from Zeiss a couple of years ago.  So, I mix and QC my own.  That may be a major advantage of Carbon-6 if what we are seeing is MIS QC problems.  I'll notify MIS of the issue.
> 
> 
> > wow..all this is starting to remind me of my days as a physics undergrad working with centrifuges and carbon nanotubes...
> 
> Did you notice the article recently that carbon nanotubes made the blackest object (print?) yet?  They're still a bit expensive for our uses in B&W, however.
> 
> Paul
> www.PaulRoark.com
>