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Author Topic: ICC grayscale optimization  (Read 2318 times)

nihil

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ICC grayscale optimization
« on: September 11, 2015, 08:57:59 AM »

What's the best way to do grayscale optimization of printer profiles these days?

I've previously used the method and "TC 2052 Gray optimization chart" at this page:
http://web.archive.org/web/20120116143337/http://www.i1upgrades.com/2011/08/how-to-use-the-tc-2502-gray-optimization-chart/

The download link for the chart is down, but I found a .cxf file with the same name on my hard drive. (I assume this is the right one) But I1Profiler won't accept this file, and seems to want a .pxf file.
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Erlend Mørk
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Alan Goldhammer

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Re: ICC grayscale optimization
« Reply #1 on: September 11, 2015, 09:23:24 AM »

I use ArgyllCMS for profiling and include a 51 step B/W patch set in the target for the profile.
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TylerB

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Re: ICC grayscale optimization
« Reply #2 on: September 11, 2015, 11:11:16 AM »

the cxf file still loads in optimization here on v1.6.3... so not sure what the problem might be. Obviously 2052 patches of gray and all sides of near gray would be an preferable way to go. I regularly used it, but have to say that with large patch count rgb profiles, an optimized build using it was no improvement. With CMYK and N channel though, it was vital, initial builds sucked in the neutral axis on early versions.
But more to the point, I wonder why your cxf file is not loading, when you hit "load spot colors" in the optimization workflow, and you are directed to "load a CxF file", how is it not available?
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digitaldog

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Re: ICC grayscale optimization
« Reply #3 on: September 11, 2015, 11:26:46 AM »

The 2502 chart works for me as well.
The cxf has to be loaded from within the Patch Set workflow. Click on Load Spot Colors... button or tiny button (3rd from left) in upper UI.
From there you can configure and save out a .pxf document.
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Andrew Rodney
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r010159

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Re: ICC grayscale optimization
« Reply #4 on: September 15, 2015, 08:10:07 PM »

It seems to me that the optimization feature of i1Profiler makes very little difference. Have others found this to be true?
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digitaldog

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Re: ICC grayscale optimization
« Reply #5 on: September 15, 2015, 08:12:52 PM »

I've seen subtle but visible differences using the 2505 target on some Epson's.
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Andrew Rodney
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nihil

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Re: ICC grayscale optimization
« Reply #6 on: September 16, 2015, 07:38:33 AM »

The 2502 chart works for me as well.
The cxf has to be loaded from within the Patch Set workflow. Click on Load Spot Colors... button or tiny button (3rd from left) in upper UI.
From there you can configure and save out a .pxf document.

Thanks! I was now able to load it. But in the Test Chart workflow the whites looks really weird. It doesn't approach white at all, just light yellow. The printed chart also looks this way. I've attached a screenshot.
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Erlend Mørk
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digitaldog

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Re: ICC grayscale optimization
« Reply #7 on: September 16, 2015, 10:47:05 AM »

Thanks! I was now able to load it. But in the Test Chart workflow the whites looks really weird. It doesn't approach white at all, just light yellow. The printed chart also looks this way. I've attached a screenshot.
That's normal.
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Andrew Rodney
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digitaldog

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Re: ICC grayscale optimization
« Reply #8 on: September 17, 2015, 04:50:31 PM »

Just to give a visual of what the 2505 gray optimization can do, here's the following. What I have is a 256 pixel ramp running black to white. On the left is the original profile prior to optimization. On the right is the optimized profile. In a perfect world, this ramp would run straight vertically and each step would be even paced.
Hopefully you can see some tiny differences between left and right in some areas (I placed two arrows where I see a difference).



Yeah, it's small, subtle but there is something going on that appears from this ColorThink plot to be 'better'. Now wouldn't it be great if the technology could account for this such the plot was perfectly vertical (neutral)? Also, this being an Epson (P600), like all Epson's I've seen, too much density in dark shadows. That's a lack of linearity in the driver I believe. Something many of us have asked Epson to address. I don't think the profiling software can do much in that respect. Maybe with a 3rd party driver with better linearization.
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Andrew Rodney
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