For those of you who think that I cannot spell 'Head', a Hedcut is a style of black-and-white drawing popularized over the years by the Wall Street Journal. Inspired by the Stipple/hedcut portraits thread in Photo Enhancements, I set out to make my own hedcut filter, based in part on that discussion, also based in part on my desire that the faux inkwork should trace the geometry of the underlying image, and also based on my whimsy that the style should also be akin, yet distinct from the WSJ. Close to my thinking are the copper plate etchings that served newspapers and periodicals in the decades before the halftone process became common. The everyday examples which survive are the portraits of people printed on currency, such as the presidents on U.S. Dollars.
Here is a representative reworking of Patrick David:

This glass plate portrait of Jean Cocteau served as my initial test image:

The filter works with color; here is Mr. David again:

The filter's effect on cartoon or line material can be quite surprising. I find this re-rendering of my avatar very amusing. I seem to be undergoing electrocution:

The filter came together fairly quickly, much sooner than I thought it would. I put it up into the Stream a couple of hours ago and it seems to be downloading from the G'MIC server nicely now. It lives in Testing ->Gmic Tutorials ->Hedcut (experimental). It should be generally available with a filter refresh.
The logic of the filter is packaged entirely in the G'MIC command -hedcut, which can be invoked in a shell with the gmic command.
Documentation of the filter is currently available at Particular Art: The Gimp Hedcut Filter
Though it did come together fairly quickly, this is still an experimental filter. Comments on its behaviour are always welcome. There are still aspects of it that I am thinking about and some elements of the user interface may yet change. Do play with it when you get a chance, and let me know what you think.

Garry

Looks cool; better then what can be down by Edges Offset alone. Looking forward to you adding it to the GIMP-GMIC plugin soon Garry.

Patrick David's blog is how I learned about G'Mic. Can't believe I haven't heard about it before now.

I couldn't get the fine detail in the above pics. Buster Keaton:

@serche
Thank you very much for testing!
I see that Mr. Keaton is very dark.

1. I suggest enlarging the image 200% as a pre-step. That was how the fine detail on Pat David was obtained: I worked oversize and then reduced after running the filter.
2. Pattern->Size: Initially accept the default of zero (smallest detail the filter is capable of).
3. Photometric->Luminance Level: I would raise it to greater than 0.5. Raise it to a value when pattern disappears in highlights, then back off a bit. Jean Cocteau was around 0.6 luminance.
4. Photometric->Contrast: With luminance set so that the pattern is almost like hairlines in the highlights, I would then increase contrast so that the pattern almost, but not quite entirely disappears in the shadow. Jean Cocteau was a little over 0.7 Contrast.
5. Pattern->Smooth/Pattern->Size: larger values on both these controls makes the pattern less turbulent and more likely to follow edges and image features.

The link to "Particular Art: The Gimp Hedcut Filter" has notes on workflow, which may help.

Thank you again for testing.
Garry

You got it, no rain but snow...
Excellent filter.
I made my first experiments:

used this as base image (from Deviant Art)


output using defaults:



...more

(continued)

output after increasing first two parameters to 0.6


output after increasing as above the first 2 parameters
plus increasing B/C of the image by 30%


finally: parameters as above, image doubled and B/C increased by 30%,
then downsized to original size


...looks good!

just to complete my tests:
same as 4th outcome but in colours and increased at the end the saturation

Nice one Garry !
anyway, it seems there is a problem with the folder hierarchy, this is what I get after an update :



There are two 'Gmic tutorials' folder, one in the other.

thanks for info

@Ronounours
Yes - I need to remove the excess hierarchy directives from the Hedcut filter definition. It is establishing its own branch rooted at wherever it is in the stream.Will patch and upload.

@dinasset
That is a very satisfying outcome! Thank you for the broad range. It is always good to see someone else use the filter, unencumbered as they by the script writer's preconceived notions.

Garry

new experiment, by combining FingerPainting and Hedcut

original (DeviantArt)


experimental outcome

Testing this out.

I wish the lines could be made smaller?

Rod,
double the image before applying the filter then downsize it back

I enlarged by 200% and used the original on Grain Merge mode.

that looks good, doesn't it?

@Ronounours
Sat down with gmictutor.gmic (my 'external source') and the prescriptions in the G'MIC Gimp-G'MIC External Source Template and found one other problem beyond Hedcut declaring its own branch: Finger paint started with a move-to-root directive (#@gimp _) but never declared what folder it belonged to (#@gimp <b>Artistic</b> was missing); the -update_server command seemed to address the issue by invoking -_update_server_move "/Finger~paint","/Artistic" on it, a remediation, I presume.
It might be a good additional link for the 'About -> Filter Design' panel in the plug in to include a third reference [3] Filter Design Template that points to the "http://gmic.eu/template.gmic" URL. I had to look around a bit to find it. It seems appropriate to have it near the location where we invite people to submit G'MIC filters and become 'external authors'. The 6:15 AM EST upload seems in circulation now and the filter directory appears to be sane again. Thank you for the heads up!
@Rod
Somehow a leopard seems especially appropriate for this toy; especially since the pattern rather imitates leopard spots. I like the outcome.
@dinasset
Laura Khavronenko's line work also triggers a lot of pattern alignment and seems apt for it. Her bold color palette seems to hold up well with Hedcut, which can dull color quite a bit. I'm not sure Hedcut is a color tool, but these paintings you've filters argues strongly otherwise.

Nice work, everyone. Thank you very much. I've thought a few other ways to apply this filter in color texturing work, where its presence is not so obvious. Perhaps I'll post some examples that I have in mind later today.

Garry

Yes, exactly Garry, I've been forced to 'patch' your file to avoid the Fingerpaint filter to appear at the root of the filter tree.
Then, I just forgot to tell you about this
I've added (and updated) the filter template file as well in the entry 'Filter design'.
Thanks for the suggestions !

Yes. I really like this effect.

Garry,
I would like to express a suggestion:
IFF (i.e.: if and only if) you verify that in the great majority of the cases the best results are obtained when the image is first upsized (to 200%?), then transformed by the filter, then downsized to the original size, it could be useful for the user to have in the filter an option to request this pre- and post-processing of the image performed automatically.
What do you think about?

Hello dinasset,
I'd say nearly everyone up scales in prep. Including me. Yes, that does seem to be the standard use case.

My thinking is to map the pattern size currently obtainable at zero setting to midrange: 0.5. That setting represents no internal re-scaling at all. Settings greater than 0.5 entail making the patter larger through spectral settings. The image size remains unchanged. Settings less than 0.5 leave the pattern at the smallest possible wavelength, but the image gets scaled upward, making the pattern relatively smaller. The default would be the midrange value of 0.5.

The scaling would be asymmetrical around 0.5 because of the change in the scaling mechanism. The geometry of the pattern will not change for scaling down from 0.5, but it will change for scaling up from 0.5. We switch from scaling the image to scaling the pattern spectrally, which will change its geometry as it grows larger. I don't think anyone would notice this anomaly.

Garry