Digital BW, The Print

On Feb 2, 2010, at 10:58 PM, David Kachel wrote:

>> Do you have the Lab A and B values for a 50% midtone of your ideal  
>> warm tone?
>
> As you probably have guessed, I am a bit out of my element here. Are  
> you referring to Lab A and B as in convert the image in Photoshop  
> and measure there?

No need to convert to Lab, just turn one of Photoshop's reporting  
panes to Lab, and sample a value that offers 50 as the first, value  
(L*) and record what the second and third values (a*, b*) are at that  
point.
>
>> What I suspect is that the brown you are looking for is both warmer  
>> than the carbons we have and has a Lab A that is closer to the Lab  
>> B value than what carbon has. Carbon tends to be more of a  
>> yellowish warm as opposed to a "chocolate" warm.
>>
>> Jon Cone's carbon sepia is probably the best warm 100% carbon  
>> inkset. There are members of this forum who can probably give you  
>> some Lab coordinates for some papers with that inkset.
>
> That might be helpful. I don't insist on an exact duplicate of what  
> I have gotten with the HP inks, but a definite, unmistakable from  
> across the room, brown is desirable. Longevity is more important to  
> me than exact color, hence my quest in the first place. Maybe the  
> general photographic community is excited about Epson's inks. I am  
> less than impressed, but unfortunately HP seems bent on ignoring  
> what the majority of the world's photographers need and want. They  
> think we all want roll paper printers and bed-sheet size prints. So  
> as I see it, the only option for serious B&W prints is a Epson 17"  
> printer with someone else's inks.

HP has chosen to neutralize its gray inks as a method of simplifying  
neutral printing. The unfortunate side effect of that it that they can  
only recommend media which happen to give the same neutrality as one  
another, to keep this "hardcoded" neutrality in place.
>
>> Finding a good, solid, true sepia or way to get to one easily is an  
>> interesting issue. My guess is that a single LK density red or  
>> orange toner might be enough, but I have not done those experiments.

That brings us back to my suggestion: that the OEM inks (two grays and  
a black, plus some colorant for the tint) are the most straightforward  
solution for such a tint. As Paul has found out, adding a colorant to  
the gray inks is not desirable, as the different pigments finter and  
settle differentially, making a consistant tone very difficult to   
achieve. So keeping your color in a seperate cart is the simple  
answer. With an OEM Canon inkset, you could do this using a Red ink.  
With the latest Wide Format Epson's it would be an Orange ink instead.  
But I'm not sure that Epson offers a 17" printer with the Orange and  
Green inks, so you may be limited to Canon. The RIP that you are most  
likely to want to use, if you move beyond the standard printer driver  
to limit your ink colors (not really necessary, but I sense you are  
determined to roll something of your own, and not use what the printer  
company has provided), would be QTR, which was developed for the  
Epsons, and has little or no support for other brands. So you might  
end up with a twin bed size 24" Epson in order to get both Orange ink,  
and QTR capabilities. No guarantees that all of this will actually  
produce longer life prints than the standard drivers, however.
>
> My background is analog B&W photography and I know that sepia tones  
> in silver prints had more to do with grain size than composition,  
> though both played a role. Is it possible to alter the size of the  
> carbon particles in suspension and if so, do you think that might  
> change the color? I wonder also if 7 or 8 ink cartridge printers  
> could be equipped with two sets of inks (3-4 cartridges each) one  
> black and one yellow (or red or orange as you suggest), the mixture  
> of which might alter the degree of brown tone so that photographers  
> would have a range of options with one inkset.

Trying to reinvent carbon ink, particle size, suspension issues,  
etc... is Alchemy, not printmaking. If thats your interest, then I'll  
leave you to the pleasures of modern Alchemy! It certainly has been an  
interesting field for Paul and for Jon Cone, but everyone else that I  
have worked with in that field has given up, gone bankrupt, or died...  
not sure that the deaths are related, but use a good respirator, just  
in case!

C. David Tobie
Global Product Technology Manager
Digital Imaging & Home Theater
CDTobie@...


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