Digital BW, The Print

"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