Digital BW, The Print

David Kachel <david@...> wrote:
>
> 
> ... Are you referring to Lab A and B as in convert the image in Photoshop and measure there?

I was thinking of the final print Lab A and B for a midtone, as measured by a spectrophotometer.  However, if you're printing on a calibrated color system, maybe the Photoshop measures of the RGB file's tones will be close.

>... Longevity is more important to me than exact color, ...

Carbon is the best we have currently in the inkjet arena.

> 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.

I'm not sure if there is an analogy here, but with carbon it appears the smaller the carbon particle, the warmer is it.  Likewise, the smaller the droplet the warmer.  Thus the 1.5 pl 1400 prints carbon a couple Lab B units warmer than an old 7 pl drop size 7500.

The coating also matters with ink jets.  So, some papers are going to be warmer than others.

> Is it possible to alter the size of the carbon particles in suspension and if so, do you think that might change the color?

At our level, we have to accept what the large pigment suppliers can provide, and they don't much care about us B&W guys.  So, we look to what the companies churn out for the large color market.  Unfortunately for those interested in warm, the large companies would rather have a neutral "core" to their color images.  So K3 LK is more neutral than K2 LK, and HP "LK" (gray) is a blended neutral-cool ink. 

> 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.

That's essentially what many on this list do now.  The K3 approach, for example, is to have 3 "carbon" (or relatively neutral) inks and then use the color inks to "tone" the carbon.  The idea with most of what we've done for a long time is just to minimize the color inks.  The Epson ABW mode, however, used more color than is necessary just to tone the carbon.  Whether the designers' goals are smoothness or controlling the tone shifts (or both) is something Epson does not tell us.  But, in any case, if you do want to minimize the color inks, you can use QTR  to control each color directly and do it yourself.  You can also pull out the excess color inks and put in more carbon.  

In early inksets I designed (UT2 for the 1280 and UT7 for K2 printers)  I mixed a pre-blended sepia and had it in the Y position.  There were also 2 positions for a cooler ink.  So, people could pull the carbon tone warmer or cooler.  I dropped the sepia because it was not as lightfast as I'd hoped.  However, there are much better color pigments out there now from the major OEMs.  If I wanted the most lightfast sepia today (beyond what carbon can do), I'd go with MIS or Cone carbon and HP or Epson color pigments. 

Paul
www.PaulRoark.com