Digital BW, The Print

Phillip Kimble <grimmieoldfart@...> wrote:
>
> 
> The Eboni K4+ approach (Epson 1400) is what I am 
> currently working with to learn 
> how to manage the Lab A & Lab B:

> K = 100%
> M = 30%
> C = 9%
> Y = 6% (thinking I may change this to 3%)

> LC = 100% C (Might change this to 30% CÂ for LC)
> LM = 100% M (Might change this to 30% M for LM)

Yes,I'd make these lighter -- easier to control and less likely to show.


> 
> What I recall is one unit of LC lowers Lab B but increases 
> Lab A 

LC will lower Lab B but also lower Lab A.  Cyan is in the bottom left quadrant of the color wheel, with a negative Lab A and negative Lab B. As an example, a Tiffen test strip with a step wedge and CMY color patches has a cyan with a Lab A & B = (-41, -47)

> 1 unit of LM increases Lab B but lowers Lab A. 

No, LM will increase Lab A. I think most of the inkjet pigment magentas have a negative Lab B, so they'd decrease it.  The Tiffen test strip's magenta = (74,0.8).  The last magenta I dealt with was the Claria/Noritsu.  It was almost neutral in terms of its Lab B also.


> 
> ... Complete control of Lab A & Lab B is the 
> goal. Though I am beginning to think it is only possible 
> using Photoshop curves.

If you have your gray (carbon) inks in K, M, C, and Y, you'll have a lot of trouble controlling the inkset with PS curves and the Epson driver.  QTR would be much easier.  Profile the carbon/gray inks first.  Then add the toners -- starting with the built in curves.  You can control the amounts with the ink limits.

Paul
www.PaulRoark.com