I think you are doing everything you can to get the colors out or reduced. I think the major problem you are going to have with this image is original resolution. It’s just too jaggy to start with. But I have an interesting approach you might try anyway:

1. Scale the image up to 4x in height and width. Yes: this will distort is more, but we are going to work on that. 2. Apply the filter set you like best for your original attempts to the blown up image. This step is really about taste, not rules, so what you will like will be different than what I will like. 3. Now apply Filters>Artistic>Oilify... to make a valiant attempt to level out the jaggies you have in the black lines/areas remaining. 4. If you want to attempt further smoothing, use the Select By Color tool to select all the black left on your image, and the switch to the Paths dialog. Use the “Selection to Path” tool to create traced paths for your selected black parts.
5. Rescale your image down to the size you want to use it in. If the master image is not quite what you think you want, try adding a new layer and then using your traced path either to trace a new outline of the black parts, or to make the path a selection and fill that with black.

Let me know how that turns out for you.

On Fri, Apr 27, 2018 at 1:56 AM ociebieda wrote:

I am already using gimp for years, not professionally, but I know most basics.
I also already used google to find proper solution, but all tutorials are not
exactly about what I need, so please do not send me links about simple black n
white or greyscale conversions.

What I need is to convert colored image to almost pure black n white effect with
smooth curves.
I am not talking about greyscale with "desaturate" or 2 color with "threshold".

Original image in lossless PNG. It has various colors that I want to remove, not making them greyscale. https://speedstar.itos.pl/gimp/gimp-original.png

Method 1. I use "threshold" with value 160, which is close to what I am looking for, but
the problem is that it makes image pure 2 color, and all curves are not smooth,
making no shades between black and white pixels (use pixel perfect zoom withot
blurring filters if you are not sure what I am talking about). https://speedstar.itos.pl/gimp/gimp-threshold_160.png

Method 2. I use "desaturate" with "average" setting, make duplicate and set layer mode to
"dodge", which keeps smooth curves and nicely removes most filling colors, but
there are grey fogs that can be noticed on chest, upper leg, and shoe. https://speedstar.itos.pl/gimp/gimp-desaturate_average_layer_dodge.png

Method 3. I use "desaturate" with "average" setting, increase gamma (not brightness, because I do not want to touch black color) with "levels" with value 160, increase "contrast" to value 96 (127 makes image 2 color), but I am still getting grey fogs slightly on chest and noticeably on upper leg, and also some
lines become too small.

https://speedstar.itos.pl/gimp/gimp-desaturate_average_levels_160_contrast_96.png

Method 4. I use "color to alpha" on all colors, make duplicate and set layer mode to "dodge", which seems to to have better effect than previous methods, but I am
still getting grey fogs that can be noticed on chest, and if I use another duplicate and set layer mode to "dodge", then lines become too small. https://speedstar.itos.pl/gimp/gimp-all_colors_alpha_layer_dodge.png

Any ideas? Thanks for any suggestions, and please, lets discuss it like intelligent adults,
no useless comments, no childish behaviors.

-- ociebieda (via www.gimpusers.com/forums) _______________________________________________ gimp-user-list mailing list
List address: gimp-user-list@gnome.org List membership: https://mail.gnome.org/mailman/listinfo/gimp-user-list List archives: https://mail.gnome.org/archives/gimp-user-list

Sent from Gmail On iPhone

It also occurs to me you might want to try this approach:

http://gimp-university.blogspot.com.es/2014/03/x-hatch.html

On Fri, Apr 27, 2018 at 1:56 AM ociebieda wrote:

I am already using gimp for years, not professionally, but I know most basics.
I also already used google to find proper solution, but all tutorials are not
exactly about what I need, so please do not send me links about simple black n
white or greyscale conversions.

What I need is to convert colored image to almost pure black n white effect with
smooth curves.
I am not talking about greyscale with "desaturate" or 2 color with "threshold".

Original image in lossless PNG. It has various colors that I want to remove, not making them greyscale. https://speedstar.itos.pl/gimp/gimp-original.png

Method 1. I use "threshold" with value 160, which is close to what I am looking for, but
the problem is that it makes image pure 2 color, and all curves are not smooth,
making no shades between black and white pixels (use pixel perfect zoom withot
blurring filters if you are not sure what I am talking about). https://speedstar.itos.pl/gimp/gimp-threshold_160.png

Method 2. I use "desaturate" with "average" setting, make duplicate and set layer mode to
"dodge", which keeps smooth curves and nicely removes most filling colors, but
there are grey fogs that can be noticed on chest, upper leg, and shoe. https://speedstar.itos.pl/gimp/gimp-desaturate_average_layer_dodge.png

Method 3. I use "desaturate" with "average" setting, increase gamma (not brightness, because I do not want to touch black color) with "levels" with value 160, increase "contrast" to value 96 (127 makes image 2 color), but I am still getting grey fogs slightly on chest and noticeably on upper leg, and also some
lines become too small.

https://speedstar.itos.pl/gimp/gimp-desaturate_average_levels_160_contrast_96.png

Method 4. I use "color to alpha" on all colors, make duplicate and set layer mode to "dodge", which seems to to have better effect than previous methods, but I am
still getting grey fogs that can be noticed on chest, and if I use another duplicate and set layer mode to "dodge", then lines become too small. https://speedstar.itos.pl/gimp/gimp-all_colors_alpha_layer_dodge.png

Any ideas? Thanks for any suggestions, and please, lets discuss it like intelligent adults,
no useless comments, no childish behaviors.

-- ociebieda (via www.gimpusers.com/forums) _______________________________________________ gimp-user-list mailing list
List address: gimp-user-list@gnome.org List membership: https://mail.gnome.org/mailman/listinfo/gimp-user-list List archives: https://mail.gnome.org/archives/gimp-user-list

Sent from Gmail On iPhone

On Wed, Apr 25, 2018 at 3:56 PM, ociebieda wrote:

I am already using gimp for years, not professionally, but I know most basics.
I also already used google to find proper solution, but all tutorials are not
exactly about what I need, so please do not send me links about simple black n
white or greyscale conversions.

What I need is to convert colored image to almost pure black n white effect with
smooth curves.
I am not talking about greyscale with "desaturate" or 2 color with "threshold".

Which version of GIMP?

carol

Hi -- just to show the results from the x-hatch version of the solution I proposed, take a look at the images in these links: https://drive.google.com/file/d/1D6WRmoq4bSJj_708GkfPKz52FaVvmKlA/view?usp=sharing https://drive.google.com/file/d/1hNtBPO2nMavE0XGnJBRyNzi9oaF0uGSb/view?usp=sharing

Just one solution. I am having trouble making the first solution I proposed work because not only is the original image so chunky, it is also very dark. If there was a way to extract the "K" layer in a "CMYK" image, it might be easier to grab just the black. I'll keep working on it and let you know what I come up with.

On Wed, Apr 25, 2018 at 2:56 PM, ociebieda wrote:

I am already using gimp for years, not professionally, but I know most basics.
I also already used google to find proper solution, but all tutorials are not
exactly about what I need, so please do not send me links about simple black n
white or greyscale conversions.

What I need is to convert colored image to almost pure black n white effect with
smooth curves.
I am not talking about greyscale with "desaturate" or 2 color with "threshold".

Original image in lossless PNG. It has various colors that I want to remove, not making them greyscale. https://speedstar.itos.pl/gimp/gimp-original.png

Method 1. I use "threshold" with value 160, which is close to what I am looking for, but
the problem is that it makes image pure 2 color, and all curves are not smooth,
making no shades between black and white pixels (use pixel perfect zoom withot
blurring filters if you are not sure what I am talking about). https://speedstar.itos.pl/gimp/gimp-threshold_160.png

Method 2. I use "desaturate" with "average" setting, make duplicate and set layer mode to
"dodge", which keeps smooth curves and nicely removes most filling colors, but
there are grey fogs that can be noticed on chest, upper leg, and shoe. https://speedstar.itos.pl/gimp/gimp-desaturate_average_layer_dodge.png

Method 3. I use "desaturate" with "average" setting, increase gamma (not brightness, because I do not want to touch black color) with "levels" with value 160, increase "contrast" to value 96 (127 makes image 2 color), but I am still getting grey fogs slightly on chest and noticeably on upper leg, and also some
lines become too small.
https://speedstar.itos.pl/gimp/gimp-desaturate_average_ levels_160_contrast_96.png

Method 4. I use "color to alpha" on all colors, make duplicate and set layer mode to "dodge", which seems to to have better effect than previous methods, but I am
still getting grey fogs that can be noticed on chest, and if I use another duplicate and set layer mode to "dodge", then lines become too small. https://speedstar.itos.pl/gimp/gimp-all_colors_alpha_layer_dodge.png

Any ideas? Thanks for any suggestions, and please, lets discuss it like intelligent adults,
no useless comments, no childish behaviors.

-- ociebieda (via www.gimpusers.com/forums) _______________________________________________ gimp-user-list mailing list
List address: gimp-user-list@gnome.org List membership: https://mail.gnome.org/mailman/listinfo/gimp-user-list List archives: https://mail.gnome.org/archives/gimp-user-list

On Sun, 2018-04-29 at 07:22 -0500, Frank Turk wrote:

If there was a way to extract the "K" layer in a "CMYK" image,
it might be easier to grab just the black.

You can use the separate+ plugin to do that, although what people think of as "pure black" for printing is not actually 0 in CMYK value - designers more often specify a rich black, e.g. Adobe Rich Black, whic (depending on the final print medium) might be 0.75, 0.68, 0.67, 0.90 CMYK respectively.

There's also undercolour removal and overprinting.

For the origial question, i'd probably desaturate and use curves with a very steep slope, the endpoints (bottom and top) close to the middle of the image.

I used desaturate, then value propagate (more black, 0.2 or so) to make the lines more robust, then curves, to make http://www.holoweb.net/~liam/download/ankhslave-gimp-original.png The curves looked like this:
http://www.holoweb.net/~liam/download/ankhslave-curves.png

liam (ankh)

Liam Quin - web slave for https://www.fromoldbooks.org/
with fabulous vintage art and fascinating texts to read.
Click here to have the slave beaten.