People's creativity really flows in this thread, it's interesting to see how different prompts give so varied amounts of responses.

@trandoductin
Cool variation on my facial image. You are right that the original is almost negative-ish, it was made it so tricky to draw too. Inverting it like you shows the image "as it should be" in a way!
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Griatch

Thank you for the patterns. I tried it out, transparency is good.
But I was hoping if there was a way to quickly tell gimp to fill it with stroke of a certain angle and specify a thickness of a certain percentage. That way you could easily match it with the shade of the gray scale image.

Try Render => Pattern => Grid, you can easily make custom width line patterns. Just break the chain in the dialog, set either horizontal or vertical to [0] and (depending on canvas size),consider using percentage [%] in the Grid dialog. Transform if need be.

Additional option: G'MIC => Deformation => Random

Yes, Tin, you can use Filters>Render>Pattern>Grid as Odin said.
Remember to make the hatch layer large enough to cover your entire image even after the hatch layer has been rotated otherwise you get odd cropping like below.
BTW, I know it doesn't quite fit with the theme (primary color) but I think I prefer it without the blue:

nice one!
I like it more without the blue as well. It has a nice feel to it.

@Trandoductin & @Jontait2, I really like the John Lennon 'hatching' images - must give it a try.

In the meantime some more primary colour images from nature -

A coloured kookaburra ...


... and Cradle Mountain in Tasmania

ooooh i really like the mountain one.

Thank you Trandoductin not just for the compliment but also for your 'mini tutorial' above to obtain a tri-colour image/portrait.

I tried it out on one of my favourite singers, Loreena Mckennit, and it worked well; then I just also ran it through 'lighting effects' slightly bumping it against the original photo ... hope you like the result!

pretty bumpy cool... yeah i like the reducing colors method much more than posterize since you seem to have more control over it telling it how many colors you want.

You should check out this script i just made and see if that helps you with hatching i didn't feel like having to create the grid and having to manually rotate and manipulate it..to me the only fun part is figuring out what colors/angle/width to use...that's left for creativity...so I hope.

Please don't ask what this is I just wanted to post something since I've failed twice in a row. xD

Figured I'd do something I never do so I decided to play with some filters...

Original Picture

For those who don't know who preytel he is, it's Adam Young who is Owl City (It's not a band! >.<).

it looks like some weird high tech video game. like it.

Aaah, I knew I knew that face, even in primary colors! Nice one!

Thanks.

Nice outcomes people, seems the art prompt is successful in luring people into trying out techniques they might not usually try.
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Griatch

This thread is responsible for sending me to the hatching scripts.

@Trandoductin - this one came out of me originally playing with your scripts, but was an accident (of which I have a lot in GIMP) ...



@Griatch - I hope you were expecting another scrabble image for this prompt ...

cool accident....the curves all connect and make that pattern...i don't think i can plan for that if i tried to reproduce it

Tran - no, that pattern comes from GMIC>contours>edge offsets'; I actually overlayed the wrong layer but I liked the outcome!

oh it all makes sense now