How to get neutral B&W with Colormunki + ArgyllCMS

[FLMK]

Hi,

Happy new yeah and I wish you all the best.

I'm new to ArgyllCMS and colormunki.

After successfully profiled colors, I have problems to get neutral B&W prints.

I explain: I've made a profile to fix colors of my printer/paper/ink.

Here are my parameters:
targen -v -d2 -G -e8 -B8 -g128 -f576 10x15cm
printtarg -v -ii1 -a1 -A1 -T360 -m2 -p100x150 -L 10x15cm
chartread -v -H -B -T0.4 10x15cm
colprof -v -qh -S AdobeRGB1998.icc -dpp -D"Canon IX6540 - Sudhaus - Tecco High Gloss (PHG260)" "10x15cm"

I've found these arguments on this forum and I've modified few of them to match to my needs.

But I have few questions about that:
1) targen -v -d2 -G -e8 -B8 -g128 -f576 10x15cm
We all have CMYK ink printers (in general)... Why does people use d2 instead of d4?
Won't it be better to use d4?
Is it because we use the AdobeRGB profile in colprof?

2) I can't have a very neutral B&W with my parameters... I still have a little greenish /yellowish deviance depending of the picture... I can't have "grey scale" prints.
For example, if I have a picture of a grass, my print is a little bit greenish.
It depends of the picture... I can't explain when it happens... In some pictures, it's visible, in others, it does not appear...
So, I think I don't have enough patches to neutral the deviance of colors.
If I take my parameters, is it better to increase -g or increase -f or both?
For example, is it better to put -g256 -f576 or -g128 -f2000?
I want to be able to print neutral B&W pictures and be able to get sepia/"chocolate"/old color cast.

3) Is it possible to get a profile (500 patches for example) initially and "add" few corrections to my profile later?
I explain: Before, I had a Datacolor Spyder3Print.
I was able to create a color profile to correct color prints (around 700 patches).
Then, If I was interested to print B&W, I was able to print and scan more patches (around 700 B&W patches) and link it to the color profile to generate the optimized B&W profile.
Is it possible to do that with ArgyllCMS?

Thanks in advance for answers.

Best regards.

Bye.

 

[Emulator]

If you look up the targen usage details you will find "The -d parameter sets the colorspace the test values will be generated in. Video gray space is assumed to be an additive space, where a zero device value will be black, and a maximum device value will be white. A print gray space is assumed to be a subtractive space, in which a zero device value will be white, and a maximum device value will be black. If no colorspace is specified, subtractive CMYK is assumed as a default."

Notice -d refers to colorspace not ink colour, our printers generally use RGB colorspace, that is -d2.

Try d4 and see what happens.

I have tried 8,8,128 myself with greys 22% of total patches and found disappointing results, however with targen -v -d2 -G -e8 -B8 -g319 -f957 which gives 33% greys, I obtained very good greyscale and colour results.

I have attached a text file which you can open in a new tab and see the structure I used for a 957 patch profile batch file.

 

[RogerB]

Hi,
But I have few questions about that:
1) targen -v -d2 -G -e8 -B8 -g128 -f576 10x15cm
We all have CMYK ink printers (in general)... Why does people use d2 instead of d4?
Won't it be better to use d4?
Is it because we use the AdobeRGB profile in colprof?

The printers use CMYK inks but they expect to receive RGB data. They are, to the outside world, RGB devices so d2 is correct.

 

[FLMK]

Ok.

Thanks for the explanations about -d2 parameter.

And what about 50% of greys?

More I have a high percentage of grey, better will it be for B&W prints or not?

Will it be more precise on B&W prints?

I've tried once 100% of grey and it failed.



And what about my question 3?

Do you have an idea about this?

If it´s possible, It would be great because we are not forced to scan lots of patched the first time if we don't print B&W pictures.
And then, if we need to print B&W pictures, we have the ability to scan more patches to complete the profile.

 

[Emulator]

My answer to question 3 is I don't know, but I doubt it. This is new ground, so you have an opportunity to advance our knowledge of ArgyllCMS!

The percentage of greys that you choose is up to you, but I believe 30% is probably as high as you need to go. Experiment and let us know. I do not think you will be able to avoid reading all the patches in one visit.

 

[FLMK]

Thanks for all.

I'll make some tries as soon as possible.

If I have news, I'll let you know.

Bye

 

[Paul Verizzo]

If, perchance, you have a Canon Pro printer, there is an extremely useful option buried under manual color control. They call it Pattern Print. In the wet darkroom, it was called a ring around. You can select fewer or more images per sheet, and less or more color change per image. Print, select the best image, then reset for finer (less variable) and run again.

Be sure to view in your preferred light, of course.

 

[Emulator]

There is a related thread on B&W here http://www.printerknowledge.com/threads/argyllcms-b-w-targen.9515/

 

[FLMK]

Hi everybody

I've done a new icc profile increasing the -g and -f values (-g433 and -f1298). I kept -e8 and -b8.

Right now, I have an other problem...

To make a test, I took a picture of the wolf here (http://moje-naruto-vytvory.blog.cz/1508/den-18-kdybys-mohla-byt-nejake-zvire-jake-by-to-bylo-a-proc) and I printed it in black and white (with a chocolate turn).

If you look closely, on his fur, I have big black spots instead of gradients...

How can I solve this?

Thanks in advance.

Bye.

 

[RogerB]

Hi everybody

I've done a new icc profile increasing the -g and -f values (-g433 and -f1298). I kept -e8 and -b8.

Right now, I have an other problem...

To make a test, I took a picture of the wolf here (http://moje-naruto-vytvory.blog.cz/1508/den-18-kdybys-mohla-byt-nejake-zvire-jake-by-to-bylo-a-proc) and I printed it in black and white (with a chocolate turn).

If you look closely, on his fur, I have big black spots instead of gradients...

How can I solve this?

Thanks in advance.

Bye.

I think you have to give us a bit more information about how you printed this image. What paper, and what rendering intent for a start. If it was colorimetric rendering did you use blackpoint compensation? It looks rather like colorimetric rendering without BPC where the black in the image simply maps to the maximum black level of the paper.

Of course it's always possible that the profile is not very good.......