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Author Topic: Argyll for B&W - number of patches needed?  (Read 21985 times)

Erland

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Argyll for B&W - number of patches needed?
« on: February 03, 2015, 10:15:35 am »

Hi!

I'm about to make a profile using Argyll, only  for B&W. What is the minimum amount of patches recommended?
Thinking about filling a A3 sheet with as many as possible and as many grey patches as possible, but I am afraid it will just get complicated with the outer points on RGB and CMY? It will only be for B&W as the epson supplied profile works great with color, so perhaps it won't matter?

Kind regards!
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howardm

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Re: Argyll for B&W - number of patches needed?
« Reply #1 on: February 03, 2015, 12:19:32 pm »

I believe that it's not (used to be OK but no longer) possible to use a BW profile w/ Epson's ABW mode.  Maybe that is only a Mac OSX gotcha.

So, you may as well just make a color target w/ enhanced # of grey and near grey unless you're going dwn the QTR route.  See the recent post (near end) .....

http://www.luminous-landscape.com/forum/index.php?topic=97262.msg796884#new

Alan Goldhammer

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Re: Argyll for B&W - number of patches needed?
« Reply #2 on: February 03, 2015, 04:11:11 pm »

The only way you can make a B/W profile with an Epson printer using ABW is with QTR.  Argyll cannot make native B/W profiles as it is not designed for that.  If you are going to use the "color" driver, you really don't need more than a 51 step B/W patch set and you need to specify this using the '-g51' command with targen.  You would need to specify a small number of colored patches so that Argyll tools will run OK.  You can print out simple B/W step wedges and read them with Argyll but you need to export the read file to Excel to get the necessary values to put into QTR.
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Erland

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Re: Argyll for B&W - number of patches needed?
« Reply #3 on: February 04, 2015, 02:13:00 am »

I was going to create a RGB-profile, using the regular PS printing, but either a custom icc profile created with several grey patches to neutralize the shadows (magenta cast today) or using curves. The icc profile created would only be for black and white, but would be a RGB profile.

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torger

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Re: Argyll for B&W - number of patches needed?
« Reply #4 on: February 04, 2015, 02:45:04 am »

I haven't done that deep research into B&W printing, but anyway in addition to gray patches (-g to targen), you want to have many close to neutral patches so the profile becomes good at fine-tuning close to the neutral axis.

You should use your existing color profile as pre-conditioning to targen so Argyll can do proper perceptual weighting, otherwise it will be difficult to prioritize neutrals.

If you have problems in shadows you can put some priority there too.

You use the -V and -N parameters to prioritize dark and neutral

perhaps this as a start: targen -v -d2 -c <preconditioning.icc> -w -V?? -N?? -G -g64 -f840 <name>
adapt patch count so it fills your A3 sheet

I don't know what a good value for V and N should be, I would suggest that you do trial and error and look at the patch distribution in a VRML viewer such as view3dscene, ie "view3dscene <name>d.wrl" after you've run targen.
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Erland

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Re: Argyll for B&W - number of patches needed?
« Reply #5 on: February 04, 2015, 04:49:58 am »

Will absolutely do that! I just made one at work, against our office printer, just to se if the greyscale became more neutral, but that was without the -N and -V parameters. I'll check and come back to you!
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Erland

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Re: Argyll for B&W - number of patches needed?
« Reply #6 on: February 04, 2015, 08:42:49 am »

Tried both parameters, And while I notices a difference in the number of darker patches using -V 1.0-4.0, the -N 0.1-1.0 was unnoticeable.
Applied an illuminant of D50 with M2 in the -f, I achieved a better tonality in my B&W.

the recipe so far is

targen -v -d2 -c "manufacturer profile" -G -e8 -g341 -f441 name

printtarg -v -ii1 -L -a1.1 -m8 -M8 -T600 -P -p210x297 name

chartread -T0.4 -H name

colprof -v -A "Marcus" -D "Plain paper grey patches" -f D50M2 -i D50 -qh -S AdobeRGB1998.icc -cmt -dpp -O  name.icc name

« Last Edit: February 04, 2015, 09:13:26 am by Erland »
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torger

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Re: Argyll for B&W - number of patches needed?
« Reply #7 on: February 05, 2015, 01:54:50 am »

Just curious, what paper are you using? The -f is intended for OBA papers.

If you like me always print with relative colorimetric (with BPC) one can skip "-S AdobeRGB1998.icc -cmt -dpp" parameters and speed up colprof significantly. Those parameters are only used for the perceptual and saturation intents.

Interesting with -N and -V, the very little I played with it I also had issues to get any meaningful results.
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Erland

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Re: Argyll for B&W - number of patches needed?
« Reply #8 on: February 05, 2015, 06:24:53 am »

Right now I was just testing a regular coated paper we had on the Shelf beside the printer. At home, where I will be using this will be Epson Premium Luster, and from what I understand it contains a small amount of OBA.
Didn't know that of the skipping of AdobeRGB for relative. Usually I use Relative, so maybe I will skip it. Took about 5 minutes creating a profile with it. Using larger patch set maybe will result in better performance gain leaving it out?

What I notices however is that the first profile I created had a relative neutral greyscale, until I put it outside, and it became green. The second using and Illu, resulted in a greyscale, though consistent, but with a Magenta cast. Viewing outside it changed into a more neutral.
Maybe this doesn't correlate the same back at home with my Epson, but still worth considering.
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torger

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Re: Argyll for B&W - number of patches needed?
« Reply #9 on: February 05, 2015, 10:42:44 am »

Right now I was just testing a regular coated paper we had on the Shelf beside the printer. At home, where I will be using this will be Epson Premium Luster, and from what I understand it contains a small amount of OBA.
Didn't know that of the skipping of AdobeRGB for relative. Usually I use Relative, so maybe I will skip it. Took about 5 minutes creating a profile with it. Using larger patch set maybe will result in better performance gain leaving it out?

What I notices however is that the first profile I created had a relative neutral greyscale, until I put it outside, and it became green. The second using and Illu, resulted in a greyscale, though consistent, but with a Magenta cast. Viewing outside it changed into a more neutral.
Maybe this doesn't correlate the same back at home with my Epson, but still worth considering.

With so good eyes maybe it's better to go entirely OBA-free, like Hahnemuhle Baryta papers? As far as I understand OBA makes it impossible to make the print appear neutral under varying light conditions. The OBA effect is usually strongest in outside light due to the higher UV content.

(Yes the difference is larger for larger patch sets.)
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Erland

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Re: Argyll for B&W - number of patches needed?
« Reply #10 on: February 05, 2015, 12:14:11 pm »

I have a Dye based printer. So glossy or luster paper is preferred. But bought some canson baryta paper just to try out.
I really like the Epson Luster, both behind glass and as small prints just to give people.

The laser paper my customers are using rarely got any OBAs, so I am not very good at on how it affects greyscale under different lighting, so I appreciate the help!
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Ernst Dinkla

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Re: Argyll for B&W - number of patches needed?
« Reply #11 on: February 06, 2015, 08:40:05 am »

I have a Dye based printer. So glossy or luster paper is preferred. But bought some canson baryta paper just to try out.
I really like the Epson Luster, both behind glass and as small prints just to give people.

The laser paper my customers are using rarely got any OBAs, so I am not very good at on how it affects greyscale under different lighting, so I appreciate the help!

Laser paper without OBAs is not that common.

Your green/orange shift looks like a typical paper OBA issue. Illu is also based on an extrapolation of higher spectral Nm values. Two variables that way; the real OBA content of the paper (ranges from Lab b 0 to -11) versus what Illu assumes and the NM range the spectrometer actually measures, some UV-cut/disabled ones stretch the data below 430 Nm by copying the 430 value. It could be that ArgyllCMS ignores the copied data though. The Epson Luster has a low OBA content, Lab b -2.9, so Illu probably overshoots the OBA content. Dye inks can have fluorescence too though and if it is an OEM color dye ink set without extra grey inks it will be hard anyway to get color constancy in B&W prints based on composite grey (CcMmY) mixes. Consistency of printer output, color setting time, display in different light conditions, fade resistance in time are all aspects CcMmYK dye ink sets have more issues with.

Our eyes/brain have the total grey tone range as a reference for any color shift Lab a b that may show along that tone range. The conditions for metameric failure/match tests are more strict with two samples to compare but greyscale prints come close to that condition on the hue failure/match. I even wonder whether the DeltaE "unit" might be too rough for B&W conditions and ICC profiling falls short then.

This week I have been brooding on special color printer profiles for B&W too, the "neutral" target patches not exceeding Lab a b values -8 to 8. This and a small gamut color space (smaller than sRGB and with a 2.2 Gamma) for the B&W images that allows color toning, neutral-sepia-selenium-split tone but gives more definition within that space and in the conversion to the custom "B&W" ICC printer profile. 8 or 16 bit. Starting from a printer that has at least 3 grey pigment inks aboard next to the color inks. In my case the Z3100 or Z3200. I thought the highest Dmax of the Zs was related to using the B&W mode of the Z driver instead of color mode in general but it looks more that it is the driver color management that keeps the Dmax high compared to application color management. Driver color management is also the setting used in the B&W mode. The driver color management is LUT based as far as I know. After printer/media calibration and with the LUT involved in the "toned greyscale" target printing I could build an extra B&W profile for the application color management. It would be double profiling of course but not impossible I think. Wonder where my thinking shows flaws .............

Met vriendelijke groet, Ernst

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hugowolf

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Re: Argyll for B&W - number of patches needed?
« Reply #12 on: February 08, 2015, 08:16:23 pm »

...  Driver color management is also the setting used in the B&W mode. The driver color management is LUT based as far as I know. After printer/media calibration and with the LUT involved in the "toned greyscale" target printing I could build an extra B&W profile for the application color management. It would be double profiling of course but not impossible I think. Wonder where my thinking shows flaws .............

Eric Chanís ABW profiles for the Epson 3800 and 3880 also relied on double profiling. When Apple made that impossible, he stopped doing them. ABW profiles are now limited to the Windows platform, and from a post a while back, Jeff Schewe implied that that time may be limited on a PC too.

Brian A
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Erland

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Re: Argyll for B&W - number of patches needed?
« Reply #13 on: February 09, 2015, 02:42:13 am »

Ernst, First, are you from Holland?

 I agree that a printer with 3 black and grey inks are preferable. Though since I am really just a hobby photographer I wanted to start out with something simple, and the dye inks in my printer are great for my type of photography, only one black cartridge is what I have to play with. However this small color space with a tiny AB values sounds pretty awesome given the simpler LUT it would achieve?

I found a way on the internet to print with just the black ink, choosing plain paper, not selecting borderless and then select greyscale within the driver. The outcome is great actually, but I can't tone it if I wanted to.
I was thinking if I made this profile in Argyll, I could create a relative neutral grey using all the inks, and slightly tone it a bit warmer, and still have a nice even tone throughout the print.

The compensation I made in Argyll regarding the OBA's was to see if it made any real difference back home. But with too much work and a sick kid at home, I haven't had the time.

The use of double profiling you talked about, If you meant selecting a color space on you image, say this small one you mentioned, and then having the printers ABW or similar selected, and still use a profile in PS print dialog, it can be done, but I think you would have to manually create and modify this print dialog profile.

I have a IPDS cut sheet printer, with CM turned on. The software they use to manage their afp data is using fogra39, and in our AFP controller we have selected a fogra39 profile as the assumed profile used on every received job. However, there is also a output profile, or actually 8 of them, All is created by the manufacturer, and is called 1A_ME_5000_XP or something similar, and is to simulate either Xerox, Mondi or IBM paper, as well as a maximum Ink amount from 200-300%.
I wanted to profile our printers, and the manufacturer informed me that this was pretty cumbersome, but if I wanted, I would create an output profile, creating it manually, since there is no way to turn of the the color management and see how the test patches would look entirely without CM in this workflow. This is doable, and I have tried, but everytime something turns out wrong.. One time the blues were way off, the other pure black always came out CMY instead. OT I know, but I think you may have to come up with something similar.

Kind Regards!
Marcus!
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Ernst Dinkla

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Re: Argyll for B&W - number of patches needed?
« Reply #14 on: February 09, 2015, 09:58:18 am »

I think for greyscale printing you are stuck between two evils, a mediocre CMYK color managed CMYK (electrostatic?) press and a CcMmYK dye color printer. If your goal is B&W prints check some cheap customised B&W inkjet printer systems developed and described by Paul Roark. A switch to that solution asks for less effort and the reward will come faster and better.


Yes, I am from The Netherlands.

Met vriendelijke groet, Ernst

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