Not too sure about the vocabulary but here is the bicolor icon I am referring to.

enter image description here

This final result should then be used for laser engraving, at roughly 4cm in size, so I need something simpler.

I'm using GIMP. So far I've tried Select > Grow by 5 pixels then Select > Shrink by 5 pixels again to remove most of the details. But this doesn't make the lines smooth enough.

What is the best method to achieve my goal?

  • I may not be understanding correctly but isn't your 2 tone icon ready for print? Can you explain more what "lower the details" means? According to the second image, it looks acceptable for the first image.
    – AndrewH
    Jul 9 '15 at 14:36
  • Hi Mathieu, welcome to GDSE and thanks for your question. If you want to know more about the site, please see the help center or ping one of us in Graphic Design Chat. Keep contributing and enjoy the site!
    – Vincent
    Jul 9 '15 at 14:48
  • @AndrewH Mmh, can you see how the second image has more straight/lightly curved lines than mine? It is definitely printable (after growing and shrinking) but I need smooth lines. Jul 9 '15 at 14:51
  • @MathieuMarques The best method would be to trace the original artwork with using the pen tool, shapes and the path finder options. There is no automated way of just "smoothing out the lines". This looks like you did an image trace from Illustrator. There are some options like when doing the image trace you can use less anchor points and smooth out curves.
    – AndrewH
    Jul 9 '15 at 14:58
  • @AndrewH Some kind stranger on the internet made that image with Illustrator indeed :). And I'm a bit afraid of how it would look lazer engraved (I used printed, but this will be engraved) on a 4cmx4cm area. That's why I was looking for a way to smooth it even more. Jul 9 '15 at 15:30

I think the fastest way to do this:

Method 1: If you already have a vector

  1. Add some white shapes on top of your graphic to hide the details.
  2. Then open the "pathfinder" panel, select all and "divide" everything.
  3. Then select at a piece of white, go in the menu "select" and choose "select same fill color". And delete the white parts.

Method 2: In Photoshop or Gimp, then vector

  1. Simply use the selection tool and fill the details areas with white. You can also use a brush if you prefer. This should be very quick, especially with the polygonal lasso tool to select the extra details.

  2. Then copy/paste that image in Illustrator and use the command "Trace", adjust the settings to your preferences, then press "expand" to make a vector out of this graphic.

Trace image in Illustrator

  1. If you want to soften the edges, you can add a stroke with a "round corner" and manually fix what you don't like.

Smooth corners in Adobe Illustrator using strokes

I don't know if there's still too many details in this example. You can fix this manually and quickly if you don't want to retrace everything and if you want to keep the asymmetry of the tracing.

Final result

Final result at 4 cm


Basing this upon comments which elude to laser etching not printing..... They are much different.

For laser etching you ideally want the vector graphic. I'm uncertain if GIMP can do that, since it's a raster-based application. This is especially true if dealing with only 4cm.

enter image description here

The original image should hold up okay. Some of the smaller detail will be lost, but the overall shape and variation should be held a bit.

If you simplify a great deal you may get better results though.... as you can see I removed all the minor intricacies of the image, reducing it to a single stroke and fill.

Depending upon the substrate being etched with the laser, your results could be similar to any of the stroke weights I've shown -- 1.5pt to 3pts. (these are estimates) On harder substrates, such as metal, you'll get a crisper etching. On softer substrates like plastic, the laser will burn away more material. On wood you tend to get the most burn in.

It is not unheard of to ask for a sample or at least discuss the art with the company doing the etching. They may be willing to run a sample on scrap material for you, or they will at least have some input as to how to improve art for their machines.

  • Thank you kindly for your dedication :). I was indeed planning on discussing of different sources and their result. This will engraved on Aluminium by the way. I assume the thing that matters the most should be the size of the lazer and how thin it can draw. Jul 9 '15 at 16:58
  • Most of the lasers are the same. It's the material which has the most effect on the size of the etching. Aluminum is a softer metal, but still metal, so it shouldn't be that bad.
    – Scott
    Jul 9 '15 at 17:00

To simplify line art, it's often a matter of just doing it by hand. Delete the extra nodes, smooth out the lines as you see fit. Lots of hand tweaking.

However, here's one more automated technique I've used that sometimes works. From top-to-bottom:

  1. Original Image
  2. Image with a slight Gaussian blur applied
  3. Image after adjusting Levels to sharpen the edges back up.

enter image description here

This, of course, was done in a raster image editor (such as Photoshop or The GIMP). At this point, you can paste the final image back into your vector tool (such as Illustrator or InkScape) and auto-trace it to convert it back into paths.

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