Digital BW, The Print

On Aug 8, 2009, at 1:41 AM, Richard Smallfield wrote:

> >in the shower this morning, it occurred to me: why doesn't Epson  
> use low-gamut pigments, as manufacturers like Cone do, to make the K/ 
> LK/LLK inks neutral - so that when printing BW, we are not balancing  
> the warm carbon pigment with the less stable high-gamut coloured  
> pigments that their coloured inks use? The high gamut pigments would  
> then only be needed in BW printing, for toned prints, or balancing  
> the tone on differently toned papers.
>
> >I can't see what downside there would be in producing perfectly  
> neutral black ink, with neutral dilutions. I can't imagine what  
> downside this would have for colour printing, either.

Your brainstorm is not unique; good ideas seldom are. This has been  
suggested in various ways to more than one printer manufacturer, by  
myself and by others, over the years. HP uses a solution related to  
this by tuning the color of their gray inks in the ink formulation.  
This is fine, but very limiting in terms of media; only certain media  
will print neutrally with such inks, so either the papers HP blesses  
for the printers are limited to a few with similar neutrality, or they  
still need a neutralization scheme involving colored inks (or both).

In terms of low gamut color in separate carts, that would require  
pricey extra heads and delivery components for those additional inks,  
unless they were to be swapped out with the high gamut color inks,  
turning the printer (at least temporarily) into a B&W machine, which  
all the manufacturers have chosen not to offer as a solution.

The most practical solution would actually be to replace light and  
dark grays (since no gray can actually be neutral on all media)  with  
three near grays for each, that bracket the gray axis, providing full  
color control on all media, no matter what neutrality they print.  
Epson discussed this system in detail with the person who holds the  
patent on it, but chose to use full saturation color inks for their  
toning of grays instead. After all, it would require 4 more colors of  
ink, and heads to run them. On the other hand it would offer excellent  
black and white, with full tonal flexibility...

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


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www.datacolor.com/Spyder3



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