Digital BW, The Print

Paul,

Thanks for the clarification on the MIS LKN ink design.  It sounds  
like there is no escaping the use of toners - either via a RIP with  
cyan and magenta or through the use of additional toned gray inks in  
order to maintain a consistent, neutral grayscale.  I was looking for  
an FSN type result, but with only two gray inks (K+LK) and this seems  
to be possible only if the LK is tailored to a specific paper, which  
makes sense.

Carl

On Jun 28, 2005, at 8:28 PM, Paul Roark wrote:

> Carl,
>
>
>> ... I'm not happy with the MIS
>> UT7 LK that I've been using in my 4000 because I've been getting hue
>> shifts (towards yellow) when printing for neutral and I have to add
>> LM and LC to get neutrality.  The whole point of switching to the UT7
>> LK was to avoid toning with the cyan and magenta inks, but It doesn't
>> work.
>>
>
> The UT7 LK(N) was mixed only to give more neutral shadows when the  
> 2200
> Epson driver was used in slider mode.  It is not an appropriate mix  
> for a
> mid-tone neutral ink.
>
>
>> Using a 50:50 mix of UT7 LC and LM position grays gets me a
>> more neutral composite gray in my 2200
>>
>
> That is exactly as it should be.  These inks are equal in density  
> to about a
> 50% dilution of LK.  I would expect the Epson lightest ink to be at  
> least a
> 30% dilution of LK.  That is about the dilution from PK to LK in  
> MIS inks.
>
> I'm starting to use FS-Y (the same density as the old PiezoBW  
> lightest --
> Y-position -- ink) in my UT7 setup to get the smoothest highlights  
> possible.
> But, its dilution is closer to the equivalent of only 8% LK.  The
> density-pigment load (dilution) curve is very non-linear near the  
> ends.
>
>
>>  I would also like to have a MATCHED, NEUTRAL K and LK  ...
>>
>
> The problem is that the same ratio of MIS R800 Blue to 7600 Cyan  
> ("RB:C"
> ratio) changes as one moves up the scale.  If one uses a static mix  
> like the
> UT1 toner, which was made for quad printers, what looks best at the  
> 50%
> patch will look very magenta in the shadows of many papers.   
> Counteracting
> this magenta bias of the shadows is why the LKN was mixed the way  
> it was.
>
> For those using LK as the neutral and highlight ink, the color ink  
> mix (RB:C
> ratio) should be like the UT1 toner.  That is what the UT2 and UT7  
> cold
> light gray inks use.  The darker cold grays, however, have a  
> different color
> mix.
>
> (Carl, if you wanted to try an educated "shot-in-the-dark" LKN-2  
> mix with
> the standard midtone color mix, I could send you a bottle.   
> However, I don't
> have the time right now to do the testing needed to get the gamut  
> such that
> it would match PKN right on.  Then again, it would be different for
> different papers anyway.  That's a major reason why I prefer a  
> variable-tone
> approach.)
>
> My next ink project is to focus on control of the shadows for my  
> upgraded
> 7600 UT7, since that can now be done with a rip.  That is, I'll add  
> control
> of the green-magenta axis in the shadows, as well as the current  
> carbon
> (yellow)-blue axis.  This project is going to have to wait until late
> August, however.
>
> Paul
> www.PaulRoark.com


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