Digital BW, The Print

On 03/08/2012 10:12 AM, Steve Kale wrote:
> That's all fine and a move to assuming a gamma of 2.2 versus 1.8 brings
> them more in line with common sense. An operating system needs to assume
> a profile when none exists in order to render an image on a display
> (although I agree one can debate which 2.2 gamma profile is assumed).
> But what OS-X appears to be doing is converting any greyscale image (I
> haven't looked at colour) to "Generic Gray Gamma 2.2 Profile" (wherever
> that came from) even if it has an existing profile embedded. It was Roy
> who first mentioned this to me. When I print an image tagged (by
> conversion) gray gamma 1.8, gray gamma 2.2 or QTR-[custom user profile]
> they all print the same on Epson ABW (and this happens with QTR) because
> each is converted to Generic Gray Gamma 2.2 by OS-X prior to printing.
> These are tagged files that are being converted.

I would not like to have that done so obscure and wrong in my OS. If 
Epson, when it adapted the ABW drivers to the new OS-X, did the correct 
thing it should assume a Gamma 2.2 Greyscale or AdobeRGB Color image at 
the import side. For targets that means assigning Gamma 2.2 before using 
the ABW route. For QTR profiled printing afterwards you should then do a 
P2P conversion in Photoshop to the QTR created profile and then assign 
Gamma 2.2 to the image before printing it.


Something you can skip as it is not a solution for Macs:

I rather have everything transparent in my workflows next to default 
choices for everyday use that stay the same in time. People learn from 
trial and error if the tools are transparent. Making foolproof black 
boxes does not educate people. Fools remain fools that way. The more if 
the basics of that black box are fooling the user. The day that the 
printer does not deliver the same color they have no clue what went 
wrong and start asking questions.  In forums like this one.

In Qimage when an image is untagged, has no color space profile like a 
profile creation target has no, Qimage will assign a color space based 
on some guessing: EXIF file etc. If it does not find anything 
informative it will assign sRGB as the default if I did not change that 
to another default setting like AdobeRGB. I can also switch that module 
off in total. I can even switch off Qimage's LCMS CM totally and that 
module will then not interfere either, nor will Windows assign a color 
space instead.

You can not do that with Lightroom or Photoshop running on recent Apple 
OSses. It is a black box. So when introduced Eric Chan had to come up 
with a detour for target printing. With Colorsync becoming more dominant 
over LR and PS  and drivers even that solution did not work anymore. The 
choice of CM-Off disappeared in PS even for Windows use where the issue 
did not exist. After months Adobe delivered the Color Utility for target 
printing, not bug free though. After that it became more difficult to 
B&W profile ABW workflows at all. And an odd other bug was reported from 
Adobe on top.

In Qimage I have three main choices in CM:
CM-OFF and the image will be stripped of any assigned color space on its 
way to the driver. The driver should be set to Let application do color 
management and I can print my untagged targets without getting a color 
space assigned by application, driver or OS.

Let Printer Driver do color management and Qimage will not use its CM 
but send the image + assigned color space to the driver so the driver CM 
can act accordingly. I have to use driver CM then of course, the choices 
of supported assigned color spaces are limited to sRGB, AdobeRGB and 
Colormatch + another one. That is the normal HP "ABW" workflow path too.

Qimage CM-ON and Qimage will do the color management conversion, I have 
to set the driver to Let application control CM.

With all I can use different B&W profiling methods if needed. One that 
is similar to my suggestion above how to overcome the Mac issues, that I 
used when Qimage did not work nicely with QTR profiles but Photoshop did.

The last 5 years nothing essential changed in the CM tools in that 
system, what has changed were improvements on what already worked 
perfect. Like allowing different rendering intends or profiles per image 
of more nested images on one print page. The last nice for comparing. A 
feature that can be used too when custom B&W printers should deliver 
different color toned images on one print page.


-- 
Met vriendelijke groeten,   Ernst

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