Digital BW, The Print

Paul,

Sounds very encouraging.  If I can get some empty carts I will do  
some experimenting with my wife's R380 printer if Roy has this one on  
his list.  I use MIS PK in my 4000 and 2400 and it is very warm as a  
BO print.  PKN give a neutral/cool BO print.

Carl

On May 9, 2007, at 12:15 PM, Paul Roark wrote:

> Hi Carl,
>
>> The Epson 4000 driver dither is already quite good
>> with just single channel BO so it might be a good
>> candidate for multiple Eboni channels.
>
> I've been testing my 2200 with multiple Eboni ink channels as well  
> as the
> 1800.  In general, the multiple channels can greatly reduce or  
> virtually
> eliminate microbanding, but it does not smooth out the grainy 2200  
> midtones.
> So, the graininess you see with BO is probably what you'll get with  
> multiple
> Eboni channels.  The larger dots to print slightly more neutral,  
> which I'd
> say is an advantage.  However, the 1800 Eboni prints on non-brightened
> Premier Art Smooth (Hot Press) 325 are definitely a tone I can live  
> with --
> just slightly warm.
>
> The very light tones are actually better with a single channel  
> firing.  I'm
> getting close to "perfect" 1800 images (with a barely visible fine  
> grain
> structure) by having a single jet fire to 25%, another one start  
> there,
> another at 50%, and another at 75%.
>
> How many channels are optimum is still an open question.  From what  
> I've
> seen 3 may be a bit too little, and more than 4 may not result in any
> visible improvement.  Whether the extra 1800 channels are useful is  
> an open
> question.  So far I'd say that as soon as Roy gets the new 260 and  
> 1400
> going, they'll make good candidates for this approach.
>
> Have you done a BO print with Epson PK?  I'm wondering how neutral  
> it is.
>
> I'm using QTR for this, with curves simply entered in the point  
> lists.  The
> channels are not partitioned, since they are all the same density.   
> The inks
> never go into a negative slope.  Right now most curves are essentially
> straight lines, with the caveat that I make the starting points of  
> all but
> the first one more gradual than a straight line would be.  The last  
> curve,
> which carries much or the black, has a highly increasing slope.  I'll
> probably come up with a more or less overall slope and then figure  
> out how
> to make the system more simple and equalize ink usage somewhat.   
> Right now I
> have not figured the areas under the curves.
>
> I'll be sending this defective 1800 back soon, but, again, I think  
> for those
> interested in a pure carbon print that will not suffer from the  
> inevitable
> differential fade of the magenta & cyan color pigments, it  
> tentatively looks
> like a viable solution for up to 13 x 19.
>
> Paul
> www.PaulRoark.com