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Author Topic: Use of Eric Chan's ABW profiiles for B&W printing  (Read 9214 times)
Farmer
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« Reply #20 on: February 28, 2012, 03:58:38 PM »
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Yes, you did, but you are not the sole director of topics.

Again, I made a simple point that the reason for the changes were due to the OS (in support of what others had said).  If you want to drag it on ad infinitum then please feel free to continue without me.

We understand you're an advocate for QTR, and that's great (it's a great system) and you've presented some good information, but the topic is a touch wider than you're trying to focus at the moment, is all.

:-)
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S Kale
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« Reply #21 on: February 28, 2012, 04:19:54 PM »
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Ok.

For ABW, little - if anything - has changed. Changes to the OS may have disrupted Eric's ICC workflow (I've not used it) but they haven't disrupted a QTR ICC profile enhanced ABW workflow. That's the simple statement I made in my first post in this thread.
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Alan Goldhammer
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« Reply #22 on: February 28, 2012, 04:36:41 PM »
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Ok.

For ABW, little - if anything - has changed. Changes to the OS may have disrupted Eric's ICC workflow (I've not used it) but they haven't disrupted a QTR ICC profile enhanced ABW workflow. That's the simple statement I made in my first post in this thread.
I'm assuming you are printing on a Windows computer system.  Phil is correct, under the MacOS system you can only print one way and one way only with ABW and that is printer manages colors.  This is because of the Epson driver and has been adequately discussed on this forum.  You can use QTR profiles with LR and PS if you are on Windows.  Now maybe you are talking about using the Quadtone RIP, it's hard to tell because you haven't been terribly explicit.
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S Kale
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« Reply #23 on: February 29, 2012, 02:06:35 AM »
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I've been extremely specific: ABW in conjunction with QTR profiles on a Mac (OS-X 10.6.8 ). If there are OS changes affecting this workflow then no one here (nor in the thread you linked to) has been able to explain them so far.
« Last Edit: February 29, 2012, 02:09:18 AM by S Kale » Logged
S Kale
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« Reply #24 on: February 29, 2012, 02:39:15 AM »
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Don't get me wrong, I am happy to be proven that OS-X is applying some sort of image transform that did not exist in earlier Printer Manages Colors workflows for greyscale documents. But statements like "MacOS no longer supports the use of profiles with ABW and Epson changed the print driver accordingly" simply don't address the issue. Epson changed its driver to prohibit access to their colour controls when Photoshop Manages Colors is set. Not a problem. As I said before, that actually makes sense to reduce the confusion for new adopters. (Colour control there = no colour control here.) The dropping of the ability to print unmanaged targets from PS is unfortunate but doesn't alone affect the ABW workflow.  

ABW was always meant to be a Printer Manages Color workflow and so, so far so good. In an enhanced ABW workflow with QTR profiles, one could always apply the transform in PS (conversion to the QTR ICC profile or, in earlier versions, application of the curve) before hitting Print thus leaving the print workflow as intended. So a profile conversion and Printer Manages Color workflow is merely this.

The question is whether the OS is imposing any other transforms/profile changes etc between a greyscale document exiting PS (with Printer Manages Colors) and it hitting the driver.  This is why I asked the question of Farmer above: "What exactly that you think happens now, as opposed to before, between a file being handed off with Printer Manages Colors and the Epson driver taking over?" His response: "No changes of importance here...". There are two aspects to this question: (1) are there any changes with respect to the way the tagged documents (the image files) are being printed and (2) are there any changes with respect to the way untagged documents are being printed (e.g. the OS compulsorily assigns a profile of some description). I would be very surprised if Apple decided to throw a loop into (1) but I guess it wouldn't be the first time. If (2) is the issue then it's a shame we don't know more about what's going on and that Adobe's print utility doesn't allow the printing of an untagged document with ABW. (If one can engineer around the printing of colour targets surely one could engineer around printing a 51-step greyscale target with Epson control control. The complication, of course, is that there is another party involved.)
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Bill Koenig
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« Reply #25 on: February 29, 2012, 12:51:47 PM »
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I haven't used Eric's ABW icc profiles, but this thread has me thinking.
OK, its always been my understanding that these ABW profiles were used for soft proofing only. After reading all of the reply's here, are Eric's ABW profiles actually profiling the ABW driver?
To be clear, if I set PS to manage color, do I select that ABW profile just as I would if I were printing color and using the correct icc profile for the paper type that I'm using? Or do I just soft proof with it and select sRGB in PS and send it off to the printer that's already been setup to use ABW for my B&W output?
So what is the correct work flow when using Eric's ABW profiles?

BTW, I'm on Windows and not locked out.
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Bill Koenig,
S Kale
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« Reply #26 on: February 29, 2012, 01:26:16 PM »
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I believe they were meant for profiling not just proofing. From reading the thread Alan linked to, I'd say the workflow associated with Eric's profiles no longer works. The question was asked there whether they would work if the image file was converted to his profile prior to sending to printing and he was unclear. The relevant post is the one Alan linked to further in this thread.

I made a comment re the use of QTR profiles and the thread progressed from there. I recognise that this discussion is under an incorrect banner (so-to-speak) and likely best sits in another thread.  The discussion is very much worth having though.
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Alan Goldhammer
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« Reply #27 on: February 29, 2012, 01:27:00 PM »
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I haven't used Eric's ABW icc profiles, but this thread has me thinking.
OK, its always been my understanding that these ABW profiles were used for soft proofing only. After reading all of the reply's here, are Eric's ABW profiles actually profiling the ABW driver?
To be clear, if I set PS to manage color, do I select that ABW profile just as I would if I were printing color and using the correct icc profile for the paper type that I'm using? Or do I just soft proof with it and select sRGB in PS and send it off to the printer that's already been setup to use ABW for my B&W output?
So what is the correct work flow when using Eric's ABW profiles?

BTW, I'm on Windows and not locked out.
Yes, they profile the ABW driver and make the response more linear.  Workflow is the same as for colored images, PS manages color (in this case ABW) and the correct ABW driver from Eric's website (you can use this to soft proof as well).  Select the ABW driver for your printer from the Epson dialog box along with the correct setting for the driver.  Although Eric is no longer providing profiles, you can prepare your own using Roy Harrington's QTR program provided you have either an i1 or ColorMunki.

Alan

EDIT Added:  I just saw S. Kale's post which appeared right before I hit the send button.  As long as you are on Windows, the current approach suggested by Eric still works.  You can both soft proof and print using the profile (and you will be able to do both in LR 4 when it comes out; I've confirmed this with the beta).
« Last Edit: February 29, 2012, 01:28:57 PM by Alan Goldhammer » Logged

S Kale
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« Reply #28 on: February 29, 2012, 01:57:47 PM »
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I would just be careful with the words "make the response more linear". What they do is map the document space to the printer space according to the chosen intent.

Epson intentionally set ABW to NOT be linear because it was built without CM execution of the above transform. Particularly for matte prints where dMax is constrained, a simple printing of file values into a neatly linearised printer response from dMin to dMax produces very poor results, flat prints that are generally lighter than expected. Epson built in to ABW tone adjustment curves to take account of this. (It's also not surprising that the default setting is "darker".)

In a classic BW RIP printing situation, the workflow involved (amongst other things) a linearisation of the printer output. But this then presented the issue I note just above: image files going from pure white to pure black jammed into a linear response from a relatively ok dMin to a poor dMax. Hence the work that ultimately led to QTR Create ICC to measure the printer response and map the image file into this greyscale gamut with an appropriate tone curve (see the kTRC tag in the QTR ICC profiles). (A colour managed workflow - e.g just printing greyscale images with a general colour printer profile - manages this remapping in a perceptual/relative colormetric manner.) This mapping was only done for luminance L* (hue a* and b* were ignored for the purposes of the transform but recorded for the purposes of soft-proofing.

So if you print a step wedge with even steps of L* (note Alan this wedge is not provided in the QTR download but if you want a tif file and its associated target txt file I will be glad to send them to you) ABW, by design, will not produce a linear L* output in its default settings.
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Bill Koenig
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« Reply #29 on: February 29, 2012, 02:29:45 PM »
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Yes, they profile the ABW driver and make the response more linear.  Workflow is the same as for colored images, PS manages color (in this case ABW) and the correct ABW driver from Eric's website (you can use this to soft proof as well).  Select the ABW driver for your printer from the Epson dialog box along with the correct setting for the driver.  Although Eric is no longer providing profiles, you can prepare your own using Roy Harrington's QTR program provided you have either an i1 or ColorMunki.

Alan

EDIT Added:  I just saw S. Kale's post which appeared right before I hit the send button.  As long as you are on Windows, the current approach suggested by Eric still works.  You can both soft proof and print using the profile (and you will be able to do both in LR 4 when it comes out; I've confirmed this with the beta).


Thanks Alan, I'm going to give the ABW profiles a go tonight.
Did you mean Eric no longer making new profiles? Here's a link to his 3800 profiles, he also a list for the 3880.

http://people.csail.mit.edu/ericchan/dp/Epson3800/abwprofiles.html
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Bill Koenig,
Alan Goldhammer
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« Reply #30 on: February 29, 2012, 02:55:36 PM »
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Thanks Alan, I'm going to give the ABW profiles a go tonight.
Did you mean Eric no longer making new profiles? Here's a link to his 3800 profiles, he also a list for the 3880.

http://people.csail.mit.edu/ericchan/dp/Epson3800/abwprofiles.html
If you go to his profile page, Eric states he is no longer making ABW profiles.
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Alan Goldhammer
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« Reply #31 on: February 29, 2012, 02:57:04 PM »
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So if you print a step wedge with even steps of L* (note Alan this wedge is not provided in the QTR download but if you want a tif file and its associated target txt file I will be glad to send them to you) ABW, by design, will not produce a linear L* output in its default settings.
I use ArgylCMS for generating targets and reading them.  It generates the correct step wedge of either 21 or 51 patches depending on which you want to use.
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S Kale
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« Reply #32 on: February 29, 2012, 04:17:55 PM »
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Okay.  For those on a Mac it's easy to use any old text editor to produce the .txt file and Colorlab (a free utility) to generate the tiff file with gaps if you prefer (which I do).
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Farmer
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« Reply #33 on: February 29, 2012, 04:21:52 PM »
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The question is whether the OS is imposing any other transforms/profile changes etc between a greyscale document exiting PS (with Printer Manages Colors) and it hitting the driver.  This is why I asked the question of Farmer above: "What exactly that you think happens now, as opposed to before, between a file being handed off with Printer Manages Colors and the Epson driver taking over?" His response: "No changes of importance here...". There are two aspects to this question: (1) are there any changes with respect to the way the tagged documents (the image files) are being printed and (2) are there any changes with respect to the way untagged documents are being printed (e.g. the OS compulsorily assigns a profile of some description). I would be very surprised if Apple decided to throw a loop into (1) but I guess it wouldn't be the first time. If (2) is the issue then it's a shame we don't know more about what's going on and that Adobe's print utility doesn't allow the printing of an untagged document with ABW. (If one can engineer around the printing of colour targets surely one could engineer around printing a 51-step greyscale target with Epson control control. The complication, of course, is that there is another party involved.)

You can test this.

Print your target using the profile both tagged and untagged.  Compare.
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S Kale
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« Reply #34 on: March 01, 2012, 06:41:44 AM »
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Yep.

After a discussion with Roy who was extremely helpful and a few tests I think I am a little closer to understanding what's happening here. Roy mentioned that he had not played around with ABW for some time but that he had found with QTR that OS-X always did a profile conversion to Generic Gray Gamma 2.2 Profile.  This is obviously a significant, and unhelpful, intrusion into the prior workflow and the fact that it isn't known to the user is very annoying.

I printed a step wedge 3 times to test this with ABW: (1) untagged, (2) converted to Gen GG 2.2 in PS (perceptual intent and BPC) and (3) assigned to Gen GG 2.2 in PS. All the prints were using ABW's default settings for "neutral" and, of course, Printer Manages Colors. (1) and (2) produce basically the same output (some printer/ink drying variance but very similar). With (3), whereby the K values are not altered by the tagging, produced a rather different L* output (most notably, unsurprisingly, in the darker regions).

Now hopefully the guys at Epson know that this is going on and that the receipt of a file tagged Generic Gray Gamma 2.2 doesn't upset their ABW driver or they've adjusted the OS-X driver to accommodate for this constant. If anyone out there can shed some light on this point it would be great.

If the above is correct then some relatively modest workflow adjustments are required to both print targets for QTR ICC profiling and final images. (Presumably this can be applied by Eric to his workflow as well.) In OS-X, we need to assign the Generic Gray Gamma 2.2 profile to the step wedge prior to printing with our preferred ABW settings (assuming we want to profile with neat steps of K). Read the step wedge and generate the profile as before. For image printing, prior to sending the image to print we need to convert the image to the QTR ICC profile and then assign Generic Gray Gamma 2.2. Then we can print with Printer Manages Colors and the ABW print settings associated with the QTR ICC profile we used.

I would greatly appreciate it if others could confirm the tests I did.

Ernst got it very close here but no one progressed that discussion in the earlier thread. Pity.
« Last Edit: March 01, 2012, 09:28:50 AM by S Kale » Logged
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