Picture of Slice Up Your Face (Again)
This one is related to

The idea is you have a picture of a face (or any image) and you want to cut it into metal or wood using a CNC tool or paint it on something or carve it into something.

You need some way to turn this really complex picture into a collection of simple shapes without losing the ESSENCE of it.

This time, I want to demonstrate a trick that involves GIMP. GIMP is a free paint program (GNU Image Manipulation Program). Find it here:  GIMP has a filter that I couldn't find in Photoshop that's kind of cheesy in just the way I need it be.

This time, I'm going to actually cut it out of something just to demonstrate that you can actually do that. The first image on this intro is a piece of 14"x14" matte board laser cut with the image described and then held up against a blue wall.

I made it at Techshop!
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Step 1: Open Your Image In GIMP

Picture of Open Your Image In GIMP
You can download GIMP from; it's free.
Run GIMP and then open your original photo in it.

Step 2: Focus On The Part You Want

Picture of Focus On The Part You Want
In GIMP, cut out everything but the face (or whatever the important part in your picture might be) by selecting the part you want with the lasso tool,  then do select->invert and then press delete.

This is an artistic choice, allowing you to focus on the most important part of your picture. Mostly though it's practical; if you do this now, you can focus all your work on something that fits on the screen.

Use image->autocrop to select just the image and cut out the white space.  Then use image->scale image to make it larger -- 2000 in it's smallest dimension should be good.

Step 3: Grayscale

Picture of Grayscale
Now use image->mode->grayscale to remove all the color.

It's still a breathtakingly beautiful and complicated image.
yellowcatt1 year ago
I have been experimenting with the technique a bit more.
I was quite pleased with how this came out.
davemenc (author)  yellowcatt1 year ago
That's cool! Did you do that in GIMP or serif or what?
I used serif for that.
It was not a supplied filter though.
I basically reproduced what I would have done twenty years ago in a darkroom. I used a line pattern to which I added some blur, this blurred line image was placed over the grey scale image and the two merged. I then used curves to increase the contrast to maximum. In the old days this would have been done using lith film and the blurring of the screen pattern would have been achieved by placing on a sheet of glass above the grey scale negative.

It is a lot easier to do on the computer and fun to experiment with different screens.
You could make tone separations and then use screens at different angles for different parts of the image.
Hmm maybe I should write an instructable on this.

yellowcatt1 year ago
Is that 'Newsprint' effect standard in GIMP? I use Serif photo plus most of the time. I will have to see if there is a plug in to achieve the same thing.

I produced quite a few images like that in the 1980s, but they were done in a darkroom using various halftone screens and lith film.
Doing it on a computer is a lot quicker.
davemenc (author)  yellowcatt1 year ago
Yes, it's standard in GIMP and GIMP is free, free, free.

Assuming you have a computer already, doing it on a computer is a lot cheaper, too.
yellowcatt1 year ago
I just had a go to see what effect I could create using some downloaded patterns in Serif. A slightly manual approach, I tried to replicate the procedure I used to create similar images in the darkroom back in the 1980s.
Here are my first attempts, best to view full size or the screening on the images will interact with the monitor screen and produce a moiré pattern.
davemenc (author)  yellowcatt1 year ago
Yep, that's the same thing EXCEPT, that I deliberately set it to an absurdly large cell size because some tools (like the plasma cutter) have an absurdly large kerf. The advantage of GIMP over photoshop (correct me if I'm mistaken) is that photoshop won't go that far down because there is no reasonable use case for it in their world... ;-)

By the way, I, too, learned about this using a darkroom and halftone screens. I guess that's where the basic idea came from... Everything in technology seems to repeat itself eventually...
Another darkroom method, which was what i sort of copied was to use a lith copy of a letratone screen. This of course gave a sharp screen, to get the halftone effect the lith screen was placed above the glass negative carrier and then the continuous tone negative printed onto lith film or paper. I will have to experiment with more DIY digital screen patterns.
davemenc (author) 1 year ago
Two things:

First, I'm sorry that I haven't actually cut this out on a laser cutter. I think the technique is useful in a lot of different ways but I also want to do the physical part, too. But there's a lot of interest in this right now so I thought I'd "seize the day" even tho I haven't gotten the last piece. I will, I promise.

Second, this one is very closely related to that one:

Now we have a much broader select of techniques for preparing an image.