Digital BW, The Print

In a message dated 5/30/07 3:39:15 PM, roy@... writes:


> It sure sounds like you are doing just as QTR-Create-ICC-RGB does -- 
> producing
> an RGB format grayscale profile.  It's not really a color ICC profile 
> because
> you can't control color with different R, G and B values.
> 
No, I'm building a color profile where the color data is minimal (the target 
print was approximately monochrome) and irrelevant (since the driver won't pay 
attention to any color components coming in anyways) but its actually a color 
profile, where the corrections are done in the 3D LookUp Table in the middle, 
not by applied curves outside of the LUT, as CreateICC does. But used for a 
monochrome driver, the results are much the same, as the other dimensions are 
moot. In other words, it linearizes the monochrome driver, and offers an ICC 
profile that previews the results. It also offers all the usual PrintFIX PRO 
tools, to adjust the gamma of prints, open the shadows further if desired, etc... 
but the color tools won't do anything in this case.
> 
> The reason I don't
> > usually print this way is that it strips all control of color, neutrality,
> > tinting, and cross toning out of my workflow, leaving that all at the whim 
> of
> > the printer driver. If I printed the same target through the color mode, 
> and
> > built a profile from that, I'd still have low metamerism results, but 
> would gain
> > neutralization for my particular paper, control of how the gray ramp 
> related
> > to my paper color, and full color control functions at the same time.
> 
> I have no problem with using a color workflow if that's what you want and 
> like.
> I just happen to like a grayscale workflow -- I find it advantageous.
> 
When I print via the Canon B&W mode, the results are not neutral, a*/b* 
values of over two units off neutral are measurable in the resulting print with the 
media I've tried (resutsl vary with different papers). If I profile via the 
color mode, I get values that are almost entirely fractional: below one unit 
from neutral in a*/b*. And if there is some type of wiggle in the neutrality (as 
paper often causes) so that its off one way in the highlights, another way in 
the midtones, and yet another way in the shadows, a PrintFIX PRO profile for 
the color mode will neutralize all of those automatically. There is no tool in 
the B&W driver mode to control such variations. Even if my goal was to tint 
my images, I first want to bring the whole gray ramp down to a controlled 
neutrality, or a controlled neutrality with consideration of papertone, and then 
tint from there. If the foundation isn't level, the house will suffer.

>   It's
> different both technically and how you think about it.  If you think in a 
> color
> workflow you'll probably see grayscale as a weak substitute, but as B&W
> printer I think in a grayscale workflow and see color/RGB issues as the 
> unwanted
> complication and in some cases detriment.
> 
If the B&W mode printed more even grays than the color mode, on any paper I 
choose, then I'd certainly agree with you. But it doesn't.   And its not 
fixable via the tools in hand. Thats my objection. But for those who find it 'good 
enough' its a simple way to print B&W. By the time you have a spectro in hand 
to build a profile for it, it seems a shame just to linearize it, and leave all 
the color wiggles in there, when with the same amount of time and materials, 
you could profile it for not just L*, but a* and b* as well, controlling all 
three dimensions.
> 
> As always, to each his own.  There's room for both approaches.
> 
> Indeed, but they need to be compared in detail to understand the strengths 
and weaknesses of each.

C. David Tobie
Product Technology Manager
ColorVision Business Unit
Datacolor Inc.
CDTobie@colorvision.com
www.colorvision.com





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