4

I am new to graphic design, and I am wondering how it's possible to convert a complex hand drawing to vector by tracing or any other method. Let's say I have an image like this: enter image description here

and I want to convert it to vector image. I have Inkscape app and only method I know is tracing bitmap, but when image is very complex and drawn by hand, my vector image has many many points and sometimes the app completely freezes. Also, tracing converts sharp edges to round edges. So the converted image differs from the original. Is there any different technique for doing this. I know there has to be something.

  • You could trace this, but you would need to identify tolerances in the tracing software that basically defines the edges of the colour blocks you want to trace. An image like that, though, I would convert to black and white before tracing. – Paul Jun 1 '18 at 7:30
  • More importantly, I would scan it, before colorizing. – user unknown Jun 1 '18 at 11:34
5

You can get good results in Inkscape with Trace Bitmap, however that image needs some cleaning up in a raster image editor first.

What you could do is open it in GIMP/Photoshop etc, desaturate it, do a levels adjustment to increase the contrast, and paint out all the shadows around the outside with a white brush.

Auto tracing works best when you have a contrasty image, with no shading. Also there's an option to switch off smoothing in the Trace Bitmap dialog in Inkscape.

For example:

enter image description here

Obviously I did this pretty quickly just as an example, but if you take a bit more care to clean up the raster image first, you'll get better results.

  • Thanks for suggestion. I knew that i have to do some preprocessing stuff in raster app. This image is easy, but was just an example of some more complex image. So conclusion is to "play" with image in gimp, clean it, remove shadows etc. – user1439198 Jun 1 '18 at 12:33
  • @user1439198 - yes, whatever the image is, you'll need to clean it up to help Inkscape's Trace Bitmap filter to see the lines. Also remember that shading or gradients will not convert well into vectors. – Billy Kerr Jun 1 '18 at 19:25
3

Generally, you would redraw it. You could try to trace it, but i wouldn't bother with that because odds are that would not give you what you want anyway. Complete workflow would look like this:

  1. Scan image in a flatbed scanner.
  2. Open in Photoshop.

    1. Cleanup noise and blemishes.
    2. Make background white with curves or levels
    3. make black actually black
    4. (optional) make image 1 channel
  3. Then either:

    1. import in illustrator, put it on a layer and make that layer template
    2. Manually draw points on top of said image

    OR:

    1. Trace
    2. cleanup
  • Thank you for an answer. Redrawing is very painful so i want to avoid this option as much as possible. I am using only gimp and inkscape, so i assume that these steps could be done by those apps, right ? – user1439198 Jun 1 '18 at 8:09
  • @user1439198 the alternative is to scan the image with so high resolution that you can just fix it as a bitmap. But this is nowehere near as much work as you expect it to be. Doing this manually would take about 2-3 hours, but yeah for a inexperienced user that might meran a week of work. But theres really no point in modifying arwork unless you do some upgrade of it in the process. You can do it i inkscape and ginp if you know what your doing. Consider the cost of not having a vector verion versus what you gain form having one, then rethink if you need it at all. – joojaa Jun 1 '18 at 8:11
3

There no shame in using raster images. You should be aware of that. A high quality, high ppi raster image is exceptionally useful in many instances. That particular image is problematic due to the low contrast background and vignetting. But a clean drawing scanned to a clean image would be more than sufficient for many methods of output.


If you really want vector, then Joojaa is correct in his answer.. redrawing is the best method.

With experience you learn to draw with vector conversion in mind - often using less detail in the drawing knowing you'll add detail in the vector artwork. It sort of gets like tattooing... you draw basic shapes, scan and manually trace those, then add all your detail in the vector application rather than by hand. This saves doing the work twice.

Barring that, tracing is pretty much the only other option, short of hiring someone to do it for you.

Different software will trace differently. You may need to experiment with different auto-trace features in various application to find one which you feel works best for you. In general, you scan as large as possible, use a raster editor to make certain the contract of the scan is high, eliminating any subtle grays and making certain blacks are black.

Essentially you have to learn to scan and adjust for the trace... most tracing features will work best with art as large as possible allowing them to see more detail.

There's no simple solution overall. I, personally, would not be able to do anything with your sample image other than redraw it due to the background and low contrast.

0

I'd give it a crack with a combination of Paint.Net and then Inkscape.

Open in paint, then cut out the area that you want to include in the image, probably just a circle, then make it black and white from the Adjustments menu. Save this as a lossless file.

Open inkscape, import the file. Right click on it and choose Trace Bitmap.

From here you will get some options for thresholds, I suspect Brightness cutoff will be the most effective, something around 0.65 would probably be a good start.

If you're missing bits up the brigtness. If you have too much noise lower it.

If not all of the image is good then you can always do 2 or 3. Then use edit paths to remove bits from ones that you don't like and group the result together.

HOWEVER, this tool does create lots of nodes, and as a result a bigger file unless you clean it up. Choosing to trace the image using the bezier tool will create a far smaller file.

0

I often vectorize ink scratchings, but I always scan them before colorizing.

Then, on scanning, I can select the resolution (600, 300, 200, 100, 50 dpi).

For vectorizing the file, I convert the PNG into PNM, because then I can vectorize it with

 potrace -s --group -o $name.svg $name.pnm

by script. Potrace itself has plenty of options to experiment with. Maybe you have a look at them.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.