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Author Topic: Linearity of ABW  (Read 14607 times)

Jeff-Grant

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Re: Linearity of ABW
« Reply #20 on: October 30, 2015, 08:56:49 pm »

Thanks John. Running the occasional test is a good idea. Printers and paper both change over time.
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keithcooper

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Re: Linearity of ABW
« Reply #21 on: November 28, 2015, 05:38:39 pm »

I've currently got a Canon iPF8300 here, with its own B&W mode, similar to ABW.

Depending on the paper, I produce linearising QTR curves (profiles) to pull the overall curve into a more linear state. Of course there's more to producing good looking B&W prints, but it helps set things (for me) on a more consistent basis.

Most of the printer reviews I've done for quite some time have a section related to B&W (some links to my efforts were kindly posted earlier) and my B&W test image has a step wedge for making the curves.

The B&W test image was originally created after I started getting papers and printers to test, and wanted some way for me to get a better feel for variations in printers and papers.
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Jeff-Grant

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Re: Linearity of ABW
« Reply #22 on: November 29, 2015, 01:33:55 am »

Thanks Keith. I have used your test image many times. For a step wedge, I prefer a 21x4 and let QTR average it for me. I've abandoned the thought of using ABW and will use QTR for K3 B&W in the future..
« Last Edit: December 13, 2015, 02:13:32 pm by Jeff-Grant »
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GrahamBy

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Re: Linearity of ABW
« Reply #23 on: December 22, 2015, 09:55:01 am »

Message removed because I was missing the point :-/
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Paul Roark

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Re: Linearity of ABW
« Reply #24 on: December 22, 2015, 11:29:45 am »

Jeff,

FWIW, I never work in the QTR linear space even though I use QTR for printing.  I prefer to stay in the relatively standard gamma 2.2 until the final print stage.  Gray Gamma 2.2 and Adobe RGB use this same Lab L curve, which has a compressed shadow area not unlike your ABW dark graph.  The Gray Gamma 2.2 curve, not the QTR linear curve is the one I would have thought it would make the most sense to compare to.

I might add that the compressed shadow area of the Gray Gamma 2.2 curve helps keep the image looking good in differing light intensities.  As the light increases, viewers simply see further into the shadows, particularly with a glossy paper.

At any rate, if you use gray gamma 2.2 as the standard, then, in fact, you can "linearize" ABW.  For some time ABW could not be combined with "Photoshop manages colors," but with at least PS CC it seems that capability is back.  So, you can make an ICC using QTR's Create ICC-RGB and combine it with ABW.  I attached a screen grab.

Paul
www.PaulRoark.com
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Alan Goldhammer

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Re: Linearity of ABW
« Reply #25 on: December 22, 2015, 02:37:12 pm »


At any rate, if you use gray gamma 2.2 as the standard, then, in fact, you can "linearize" ABW.  For some time ABW could not be combined with "Photoshop manages colors," but with at least PS CC it seems that capability is back.  So, you can make an ICC using QTR's Create ICC-RGB and combine it with ABW.  I attached a screen grab.

Paul
www.PaulRoark.com
Paul,  I cannot tell if your screen grab is from a Win OS or Mac OS machine.  Certainly under Windows one could still use ABW profiles even when the Mac OS prevented this.  I don't think it's a function of Photoshop CC since it was OS dependent.  Maybe things have changed with the newer Mac OS.  We had an extensive discussion of this several years ago here on LuLa
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Paul Roark

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Re: Linearity of ABW
« Reply #26 on: December 22, 2015, 04:40:14 pm »

I am on Windows 7.

In general, on the Windows platform there were, in the past, problems making or using the ICCs.  Even my CS5 (unlike the PS CC) still wants to change its print screen in response to the printer driver settings.  Whatever the issues were in the past and with the combinations of hardware and software I had, Win 7, PS CC, and the drivers I'm now using don't seem to have any of those issues.  Things seem to work as they should.  Thus -- the bottom line -- ABW's consistency with a usual, for example, Gray Gamma 2.2 & Adobe RGB printing characteristics can be dealt with using ICCs, at least in my setup's environment.   

A connected issue is that for QTR printing, I use a PS curve that adjusts between Gray Gamma 2.2 and QTR's straight line printing characteristic.   I prefer to keep my files in the relatively standard Adobe RGB/Gray Gamma 2.2 spaces as long as possible. 

Paul
www.PaulRoark.com
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Alan Goldhammer

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Re: Linearity of ABW
« Reply #27 on: December 22, 2015, 05:04:50 pm »

^^Thanks, I also am on Windows and have prepared my own ABW profiles which work quite well.  Even when I built a new workstation and moved to Windows 8.1 and new drivers for everything I didn't see any issues at all.

Alan
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Paul Roark

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Re: Linearity of ABW
« Reply #28 on: December 29, 2015, 11:50:09 am »

BTW, if you make profiles with the QTR Windows GUI Curve Creator in Win 8 or 10, there is an annoying bug.  When you hit "show curve," it will not show.  The way you see the final curve is to right click on the list of profiles in the main GUI.  The option to show the curve appears there and works.

The Curve Creator bug affects both the "show curve" button and File>Save method of saving the Quad files.  Those files are generated and saved, but then the system hangs and the cursor's spinning circle, indicating it is busy, will not stop.  You can ignore it, but it's annoying.  To stop it, go to the main GUI and do a File>Open.  This turns off the spinning circle.  While this stops the annoying "busy" signal, the software is stacking up unfinished business that does not show.  If you are making a number of profiles, this will eventually slow the system.  To clear it, you need to shut down QTR and re-open it.  As you shut it down, you'll see the blank curve boxes flash on the screen.

Aside from this annoying but non-fatal bug, QTR works fine with Windows 10 as far as I could see in my short time experimenting with it on my wife's Win10 Dell.  (I have no intention of "upgrading" to Win10 on my Win7 machines.)

Paul
www.PaulRoark.com
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