Digital BW, The Print

Hi Clayton,

I'm no ink expert, so a lot comes down to my gut feel.  I also totally
agree that much is unproven so its better to err on the conservative side.
If I had my druthers I'd probably want a gray set that was my most used
color and just use extra toner for variation from that.

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Clayton Jones" <cj@c...> 
wrote:
> Hello Roy,
> 
> >There seems to be an ongoing notion that there are two distinct kinds
> >of B&W prints: some made with pure carbon inks and others that use
> >color inks and therefore somehow inferior.  But all of the methods
> >that produce neutral-tone B&W involve color pigments.  The majority
> >is always carbon pigment, but they all have color pigment added to 
> >give the desired color.  
> 
> In a recent phone conversation with Bob at MIS he expressed his own
> doubts about the RIP approach, echoing my own concerns.  The
> implication (as I interpreted his remarks) was that the amount of
> color pigments (which he said are made of "various polyesters") used
> in the RIP technique is greater than the tiny amounts mixed into the
> carbon inks of gray scale sets (I don't know if anyone has actually

I don't see anyway that the amount of color pigments can be different.
If there were more cyan & magenta the print would be bluer.  Its not
like the Epson driver where CMY are all mixed and cancel each other out.
The neutral profiles all use only LC and LM no Y.

> calculated the difference).  He said that the mixed in amounts are not
> significant enough to affect the "carbon status" of the inks.  Paul
> Roark recently expressed similar concerns (see msg #43963, 4/16/04).
> 
> Of course longevity is relative.  I don't remember exact Wilhelm
> numbers, but I do recall reading that the carbon blacks outlasted the
> color pigments in one of his tests.  If the cyan/magenta dots in a RIP
> print last 70 years and the black lasts 100 then you have a 70 year
> print.  Is that "archival" enough?  Will a gray scale ink print
> outlast a RIP print?  

But on the print its exactly the same stuff, the same amount of carbon,
the same amount of cyan pigment and the same amount of magenta
pigment.  If the carbon lasts 100 and the colors last 70, then after
70 you will have a warmer print in both cases.

Will a pure carbon Eboni BO print last even
> longer?  Nobody seems to have a definitive answer.
> 
> My own tests give me doubts about pigments.  I have a Septone print
> (multi-tone gray scale inks) on my windowsill that began showing signs
> of fading at 125 days.  Right beside it is an Eboni BO print (both on
> PhotoRag) that is over 150 days now with no signs of fading.   Of
> course that's an unfair torture test (bright daylight and a small
> amount of direct sunlight every day), but it nevertheless shows a
> difference in the inks.  I plan to do a windowsill test on a UT7 print
> when it's available.

Do you have any test using the MIS beside Eboni?  

> 
> So...what to make of all this?  I don't know, I just have doubts about
> the colored dots.  If I'm going to have dots I guess I prefer them
> to be all black <g>.  

It's certainly reasonable to be safe.  Until they outlaw loupes someone
will always try looking at the details.

The only thing I do have some confidence about
> is I can say that my prints are pure carbon ink prints and that Eboni
> ranks among the highest (if not _the_ highest) in longevity ratings. 

Eboni seems to be quite different than the Epson inks. Its too bad that
there doesn't seem to be a dilution capability.  My guess is that the
carbon particles are larger in Eboni.  This results in better longevity
and I believe also why the tone is more neutral.  As I recall from
darkroom papers, the warmtone papers had smaller grains of silver.
The small grains appear warmer that the larger grains.

> Beyond that, I'm just waiting to see what happens next.
> 
> Do you know if there are there any gray scale inks without toners,
> just dilutions of black carbon ink?

Sure, its just that they aren't neutral tone.  Piezo Carbon Sepia is supposed
to be.  The new MIS FS-UT is I think.  Part of the appeal of toners is
that the grays are pure carbons so you can make a pure carbon print.

> 
> Regards,
> Clayton
> 
> 
> Info on black and white digital printing at    
> http://www.cjcom.net/digiprnarts.htm

Regards,
Roy

www.harrington.com