Digital BW, The Print

> From: Paul Roark <paul.roark@...>

> 
> OK, BPC is used to take care of the end point issues, as I understand it.
> 

The ICC spec actually misses out black point compensation/scaling. It is
fully geared for white point compensation but not the black end.  This is
why Adobe has BPC to manage the black end.  So BPC is only managing the
black end of the scale (not the white point scaling).
> 
>> ... in XYZ (for B&W we only care about Y)
> 
> I thought Y in CIE XYZ was green.  Or do you mean the Y in xyY?

No.  It is luminance. Pg 10 s6.3.2 of the spec describes the scaling for
media relativity.
 
> 
>> ...
>> BPC scales the data such that the curve begins at 0,0.
>> So when you send pixel value 0 to the printer
>> it gets left at 0 and hence prints as dark as the printer possibly can.
> 
> This is what I'd want.

Yes and no.  A problem with an ICC profile which shows a perfect black point
(such as when embedded BPC scaling has been done) is that when you go to
soft proof PS says your printer can produce perfect black and hence your
deepest blacks are shown as monitor black even when you check Simulate Ink
Black.


> 
>> ...
> 
>>> Is the QTR Curve Creator Linearization tab a look-up take interface?
>> 
>> Now it is. 
> 
> 
> I think I'm only able to open the Curves Creator and not the
> "QTR-Create-ICC.exe."  Is this just a Mac program, or does it require i1?
> (It's in the i1 folder.)

It's a droplet.  Drag your data file over the app icon and simply let it go.
A Windows user can describe this more accurately if I am wrong for Windows.
All this stuff is in the i1 folder because originally Carl found a way to
use MeasureTool (part of GM's PM5) to strip read step wedges for
linearization.


> 
> 
> 
>> ... [Roy's] aim is to proof hue and luminance correctly.
> 
> Ultimately, that could be useful, but for the B&W I'm targeting now it's
> complexity that gets in the way of the basics of B&W printing.

Not really.  This is a powerful advantage of ICC profiles.  You get to see
what warm looks like etc.
> 
>> ...  ICC profiles have the advantage
>> that people can set up soft proof in the normal fashion.
> 
> That sounds like another complex story.  If we're in PS the custom dot gain
> curves do it, but we do need to get a simpler method.

I'll address this in another post.


> 
> 
> ...
>>> Is there a place that describes the specific ways in which a
>>> Windows XP user
>>> can use QTR to make an ICC that can be used in the Print with Preview
>>> workflow and then the Epson driver?
>>> 
>> Not sure but it is really very easy.  Print a step wedge with the workflow
>> of your choice eg Epson Adv B&W with a particular set of settings.  Scan
>> the
>> step wedge with an EyeOne or other device that will provide the sort of
>> data
>> QTR Create ICC can read. ...
> 
> I'm not sure I can even open Create ICC.  So far I just get a momentary
> flash on the monitor.

Described above - don't run the app just drag your data file on top of it.
The data file is a simple text file.  I thought Roy, at the time of his new
QTR version announcement, described its basic format.  I can send you an
example of the output from MeasureTool but I believe Roy has made the
program capable of reading a more general data format.


> 
> 
> 
> 
>>> Are those ICCs useable in the Print with Preview procedure
>>> with the Epson driver?
>> 
> 
>>   Yes I use them all the time.  I have profiled my Epson Adv B&W
>> settings, one for each hue - neutral, warm, sepia and cool.  I do not mess
>> with the darker and other settings (other than hue).  I prefer to edit the
>> image in PS rather than in the driver which has limited editing ability.
> 
> The possible advantage with using the driver controls as much as possible is
> that they may well be doing hardware linearization in the driver -- with no
> loss of grayscale steps.  The ICC or TF in the Print with Preview -- or
> anywhere in PS -- loses some information with each transformation.
> 
> Interesting stuff, but I don't seem to have an easy way to make the ICCs at
> this point.


Once you get the drag and drop thing then all you need is a text file in the
right format.