Digital BW, The Print

dgattarino wrote:
> Thanks from the few of you who answerd my question.
> However, none of the replies mentioned the reason for the number they
> quote as the minimum number black inks for fine art B&W.
> I made a couple of considerations in the meantime:
> 1) The gray shades where the print start to look poor ar the lightest.
> That's where the dots from the print start to become visible.
> I have never seen such dots in the mid or dark tones
> 2) From a recent post from Clayton Jones
> (http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint/messages/78918?threaded=1&m=e&var=1&tidx=1)
> it appears that the gray ink used by far the most is LLK. This means
> that LLK has to cover a larger range of tones by itself, when compared
> with the other gray inks. Therefore, it might need some "help" from
> another gray shade.
>
> The above considerations would suggest that the minimum number of gray
> shade for best results is, infact, 4 with a LLLK supplementing Epson's
> LLK in the highlights.
>
> I would like to know what you think about the above.
> Thanks. Cheers,
>    Daniela
I make no claims of authority, but I'll give you my take. The assumption 
I'm making in the following is that the goal is high quality "dotless" 
prints.

You need at least three inks. A black and two grays. Depending on the 
printer, this may be sufficient if everything is perfectly aligned, and 
the print head is in the center of it's design tolerances. No deflected 
nozzles, no alignment problems, all that.

The problem is, there aren't any three ink printers out there. When this 
all started, there were four ink printers (CMYK). So most of the 
pioneers used four inks (black and three grays). This put inks in all 
four slots, and took significant pressure off the hardware/software 
being really good. With four inks you can generally get quite nice 
results. Quad-tone inksets work really well.

When six ink printers (CcMmYK) came out, what most of the manufacturers 
did was to duplicate the most used inks. IOW, you were still using 
quads, just with a couple of positions doubled.

Only recently has software come available to allow direct control of the 
individual ink channels in printers (QTR, StudioPrint, IJC, others). 
This lets us have six, seven or more individual ink densities to play 
with. Many people think you get better tonality - smoother prints - 
using a black and five grays. As a result, hex-tone and sep-tone inksets 
are becoming more common.

So, to answer your question, I think the minimum number is three. The 
minimum *practical* number is four. The biggest bang for your buck is 
probably six-eight. I doubt there's any reason to do 12, but we won't 
know until someone tries it ;-)
-- 
Bruce Watson
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