Digital BW, The Print

Alex:

You wrote:  >And, if one was to print a color photo directly with a 
Hex grey set of inks, it Is required for the magenta to be the darker 
ink for image fidelity.

Is your goal to develop a B/W inkset with the positions and densities 
that you can use to directly print a 24-bit RGB color image and get a 
natural looking grayscale picture without first converting to 8-bit 
grayscale or 24-bit grayscale and *colorizing* it with partitioning 
curves?  

Jeff Randall


--- In DigitalBlackandWhiteThePrint@y..., "a_pettit_jr" 
<a_pettit_jr@y...> wrote:
> Hi Jeff,
> After additional microscopic examination of a greyscale (printed in 
Color), I can conclusively state:
> the Epson2000P driver 
> 1) uses Black ink only above the 80% black level
> 2) the full color CMs are used from 50% and above
> 3) the PC and PM is used from 1% to 50%
> 4) Yellow is used throughout the range (perhaps not above 95%)
> 
> It seems that the grey shades are pretty much a balance of C and M, 
so it probably does not matter which is the darker tone, but there is 
( perhaps metameristically ) an increased magenta tint in the darker 
shades. And, if one was to print a color photo directly with a Hex 
grey set of inks, it Is required for the magenta to be the darker ink 
for image fidelity.
> 
> Also, from what I can observe, it seems incorrect for the PCe to 
nearly equal the M in density. I plan to create one new shade for the 
first trial and resequence the inks. I ordered some empty carts to 
test my 'theory' before filling the CIS set.
> 
> Later,
> Alex
> 
> 
> --- In DigitalBlackandWhiteThePrint@y..., "jrandall1149" 
<jrandall@c...> wrote:
> > Alex:
> > 
> > My working knowledge of the Epson driver (others please step in 
and 
> > help/correct me because I am beyond my detailed technical 
knowledge 
> > of drivers) is that it does not not see in grayscale, meaning 
that it 
> > does not cause the ink in the Cyan position to fire when it is 
sent a 
> > certain brightness/luminosity/lightness/density value. It fires 
when 
> > sent a CMY color of a given brightness. In grayscale mode, I 
suspect 
> > that the CMY information is close to equal creating various shade 
of 
> > gray depending on the brightness information sent to the driver.
> > 
> > I haven't checked it out, but I suspect that the Woolf workflow 
would 
> > work with the gray inks in any positions (but K=K) because it 
treats 
> > all the gray inks essentially the same -- hence the brightness of 
> > each Woolf dot is the same until K kicks in at about 50%.  BTW, 
the 
> > Woolf curve is not very aggressive and seems to fit my 
understanding 
> > of your goal of mild correction.
> > 
> > The only way that I know of to control the individual inks in any 
> > particular position with the Epson driver is to assign colors & 
> > brightnesses to the grayscale image--this is called partitioning. 
> > Roark, Brandon, and Randall workflows (found at MIS 
> > www.inksupply.com) are examples.  
> > 
> > You may have hit on something about the sequence of ink 
deposition 
> > creating an additional variable.
> > 
> > Jeff Randall
> > 
> > 
> > > >