instructables

Slice Up Your Face (Again)

by davemenc

This one is related tohttps://www.instructables.com/id/Cutting-Out-Your-Face/

The idea is you have a picture of a face (or anyimage) and you want to cut it into metal or woodusing a CNC tool or paint it on something or carve itinto something.

You need some way to turn this really complexpicture into a collection of simple shapes withoutlosing the ESSENCE of it.

This time, I want to demonstrate a trick that involvesGIMP. GIMP is a free paint program (GNU Image

Manipulation Program). Find it here:http://www.gimp.org/ GIMP has a filter that I couldn'tfind in Photoshop that's kind of cheesy in just the wayI need it be.

This time, I'm going to actually cut it out of somethingjust to demonstrate that you can actually do that. Thefirst image on this intro is a piece of 14"x14" matteboard laser cut with the image described and thenheld up against a blue wall.

I made it at Techshop! www.techshop.ws

1. Oops, one extra cut...2. This image is cut out matte board set up against a blue wall andappropriately cropped.

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Slice Up Your Face (Again): Page 1

Step 1: Open Your Image in GIMP

You can download GIMP from www.gimp.org; it's free.Run GIMP and then open your original photo in it.

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Step 2: Focus on the Part You Want

In GIMP, cut out everything but the face (or whateverthe important part in your picture might be) byselecting the part you want with the lasso tool, thendo select->invert and then press delete.

This is an artistic choice, allowing you to focus on themost important part of your picture. Mostly though it'spractical; 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 cutout the white space. Then use image->scale image tomake it larger -- 2000 in it's smallest dimensionshould be good.

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Step 3: Grayscale

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

It's still a breathtakingly beautiful and complicated image.

Step 4: Brighten Your Day -- and Your Image

Now you need to brighten your image. Use colors->brightness-contrast... to call up a dialog box. Enter a number(or slide the slider) for brightness. You want it to look kind of faded or washed out; it probably isn't bad to go "toofar".

For this image I used 70. An image with a lot of white in it should get less; a darker image more. The key is that thedark parts should be dark gray and the light parts almost white.

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Step 5: Slice Your Image

Use filters->distorts->newsprint... to bring up thenewsprint dialog box. Set cell size to 40, set "spotfunction" to "line". You might, depending onpreferences and artistic license, set the angle tosomething other than 45 degrees -- I set it to -45because I thought it looked a little better. Now click"OK".

Now go to the bottom of the window and change thezoom (it has a percentage). Click on the littlepulldown and select 12.5%. Does it look like yourimage?

Now select 200%. Are there any parts where thewhite lines are either completely cut off or very

narrow?

If you can't recognize your image then you need to doctrl-z (undo) and try again with a lower number.

If you can recognize your image but the black linestouch (or come very close) go back and try again witha higher number.

If you have both problems go back to the brightnessand brighten it more.

You may have to play around a bit to get this to workthe way you want it.

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Step 6: Maybe Dots Are Better

There is another way to do this using the same tool:"round". Round will probably look better but it maytake longer to cut. You might be able to have theimage be darker and have it still work.

To use round, change "spot function" to "round". Youcan probably change the cell size to a smallernumber; I used 30.

Once again, you need to make sure that there isenough white space for your material to hold together.

An interesting option here is to print this pattern on toa piece of paper, lay it over your material and thendrill out all the black stuff with an ordinary drill. Since Ihave access to techshop, I can use their CNCmachines to save myself that trouble.

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Step 7: Save Your Work

Use Export (ctrl-E) to export this file to a jpg. Then run coreldraw.

Select file->new to get a new document and then import your image into coreldraw using file->import.

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Step 8: Turn Bitmaps Into Vectors

Most CNC tools need a vector, not a bitmap.

In Coreldraw, right click on the image, select "outlinetrace"->detailed logo. Make sure "delete originalimage" and "remove background" are checked.

Right click on the object and select properties. In theproperties panel (to the right) select the pen tab andset with to "hairline". To see what just the lines look

like, go to the bucket tab and select the "X" under"fill".

The 2nd and 3rd images shows the tool path and thecut away respectively. This is instructive because thetool path image doesn't look like anything but it willproduce a result very much like the other one whichlooks like the original in some strange way.

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Another Dave here. Just wanted to say thanks for the quickie Gimp tool tip. I'm referring to the cut-out-image-lose-background action. You should write Gimp tutorials. They need you. Quick, simple,

Step 9: Same Again But With Dots

Ok, again with the dots. You get this exactly like the lines but just use the dots image you created in GImp.

Step 10: Ready, Set, Cut

I'm going to cut this on the laser cutter because I think the lines are too close together for the plasma cutter.

Export it as a coreldraw file, put it on a thumb drive and then use the computer connect to the laser printer to "printit" .

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1-2-3's for a specific ACTION, rather than a long-winded "Chilton Manual" type chapter for one littletool. ~David, a.k.a. the ConnMan.

Thanks. I'll consider that. I did a similar thing for coreldraw here on Instructables -- the 10 "mostneeded operations in CorelDraw". I could do a similar thing for Gimp. Assuming I can figure outwhat they are. Like most people I usually use a paint program to crop and size images.

I have been experimenting with the technique a bit more. I was quite pleased with how this came out.

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 linepattern to which I added some blur, this blurred line image was placed over the grey scale imageand the two merged. I then used curves to increase the contrast to maximum. In the old days thiswould have been done using lith film and the blurring of the screen pattern would have beenachieved 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 theimage. Hmm maybe I should write an instructable on this.

Is that 'Newsprint' effect standard in GIMP? I use Serif photo plus most of the time. I will have tosee 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 usingvarious halftone screens and lith film. Doing it on a computer is a lot quicker.

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.

I just had a go to see what effect I could create using some downloaded patterns in Serif. A slightlymanual approach, I tried to replicate the procedure I used to create similar images in the darkroomback in the 1980s. Here are my first attempts, best to view full size or the screening on the images will interact withthe monitor screen and produce a moiré pattern.

Yep, that's the same thing EXCEPT, that I deliberately set it to an absurdly large cell size becausesome tools (like the plasma cutter) have an absurdly large kerf. The advantage of GIMP overphotoshop (correct me if I'm mistaken) is that photoshop won't go that far down because there is noreasonable use case for it in their world... ;-)

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By the way, I, too, learned about this using a darkroom and halftone screens. I guess that's wherethe 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 letratonescreen. This of course gave a sharp screen, to get the halftone effect the lith screen was placedabove the glass negative carrier and then the continuous tone negative printed onto lith film orpaper. I will have to experiment with more DIY digital screen patterns.

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 alot of different ways but I also want to do the physical part, too. But there's a lot of interest in thisright 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: https://www.instructables.com/id/Cutting-Out-Your-Face/

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

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