Tracing bitmap in vector editors and parsing it back in raster image

Kinda cool oilifying effect





original photo

The same lady again

How many trace layers are you using in the vector program? Playing with that number can give interesting results.

Tracing in either Inkscape or Ai creates one trace object, always in one layer. Then you can ungroup it and sent to different layers.
Is that what you mean, Odin? I've never seen an option to create multilayered trace. Am I missing something?

Sorry, my wording was not right I should have said scans. In the Inkscape options you can change the scans, I think the default is 8.

Oh, I see what you mean now. Thanks for pointing that out, Odin!

One of the earliest artistic effects that I started out with was vector simplication K1TesseraEna (back in the late 1990s/early 2000s) which sort of got me into the whole retouch bug in the first place. Looks like you are well on the way of catching that same bug too. Kudos to living with your future and lifelong disease. lol

What prog did you use back then, Lyle? Are you talking about Potrace?

Hijaak; believe they are still in business (not sure though). Slow as molassis when the image was bigger then 640X480 (pretty much standard back in the late 90s; lol).

Never heard of that program But what you said before, it's not the artistic effects i'm after. Just trying to find out how good is vectorizing for upscaling small size images. What I posted here was kind of cool byproduct of the failed attempt. The original photo is about 450x450, after vectorizing with good enough tracing I can scale it up to any sensible size.
What todays software can do at converting pixels to vector paths is truly amazing.

@Lyle

That rang a bell, I worked for a number of years in the middle east & east asia, and for lack of better things to do, became a collector of dubious software. Hijaak is still there in my archive.

@K1TesseraEna

Your portrait turned out very effective.
For small images, as with anything graphics it depends on the subject what process to apply. I did a video not so long ago, using Gimp and potrace. It is in linux but some pointers for windows users.

*** warning it comes from another forum, so be tolerant ***

http://youtu.be/bhHACVo_pKE

One question for the tracers out there (I once opened inkscape for the curiosity but nothing much).

When you trace a photo like that, what become of the original color space, is inkscape operating a color conversion, or is it still the same sRGB image ? My question is related to printing issues, you know, do I need a cmyk image or an rgb one, these annoying details.

@anarkhya
Interesting question. When you open raster image in Inkscape it asks you to either link or embed the image. SVG specifies color profile in sRGB color space. But if your image is in CMYK and the Scalable Vector editor (Inkscape, AI, CorelDraw) supports CMYK color space it will take the precedence over sRGB. SVG specification allows other ICC color profiles . AFAIK, Inkscape does not support CMYK, therefore you need to convert output bitmap to CMYK with other program. GIMP doesn't support CMYK either, you need Separate+ plugin for that.

Scribus has something to convert bitmap in vectors ?
Just wondering Inkscape give me same headaches than Illustrator , scribus looks simpler
(may be my mental setting, if i have to spend so much time learning and practising at least i want a scalable 3D object as result ,no less
, that learning effort is too much for me to only do something in 2D
i like learning but i must get good results also during the learning process, not only as future goal or i loose quickly loose interest and drop, as happened for vectors graphic)

Just a few observations

Although an RGB application Inkscape will import a cmyk bitmap. Not tif but jpeg is ok (at least on my PCLOS Inkscape)
Tracing a complicated image such as a portrait will end up with a reduced colour set, much like posterization. Tracing works best on say logos with solid colours.
Whether traced or not your image can be saved as an SVG or exported as a RGBA .png file. Both import into Gimp with good results.
There are Inkscape extensions that will export to a CMYK image. The one I use OutputPro is linux only and jpeg only but it does a good job of embedding color profiles. There are others (I think work on windows) which export to cmyk tif. Tried and they do open in Gimp with separate+
link for anyone interested http://www.inkscapeforum.com/viewtopic.php?f=11&t=5943

@rich It's true, you can load CMYK jpeg in Inkscape and convert image to CMYK color space but only as an output file. While the image is still open in Inkscape it is always sRGB. I think that's was anarkhya was asking.
I'm using AI that has built-in CMYK support, meaning it is not only able to import/export CMYK profile images but, if not mistaken, also operates in this color space.
There is a simple test. Open CMYK jpeg in Inkscape and export as bitmap. It will not pass on the embedded into imported image CMYK profile. The output file will always be sRGB (unless you use the extension CMYK conversion).


@PC. No, I would not use Scribus for that. It's true, Scribus (like Inkscape) can import raster image and export as SVG without tracing. But it's not the same as tracing.
Try to export that vector image as large size bitmap, you'll get the same jagged raster image as if you were upscaling in GIMP or PS using simple bicubic interpolation.

ah ok, i was only interesting to find a EASY (without have to try to learn again all the vector graphic basis ) way to do tracing

I have Inkscape (even Illustrator ) but i almost never open them

Well I was asking the question because the first traced image in this thread looks, color speaking, really close to the bitmap one, and from my very little printing experiments when you print a bitmap you find out that there's a gap between the colors you see on a screen and the color you get on your paper, and in the worse situations you encounter the "impossible" colors issue (IIRC because CMYK can't do all the colors sRGB has).

So, my point was: do inkscape convert colors into some kind of safe-printing-mode or is it a more complex problem ?

You might want to first checkout out, Color Management. Be aware the color profiles can slow down Gimp. One other thing to check, Image menu >> Print Size. Inkscape has no advantage over Gimp with printing, Gimp has the advantage for preparation.

I understand why you were considering Scribus, it's superior to both Gimp and Inkscape for pre-flight and printing. One other thought; there is a good chance the best printing software on your machine (not the driver) is bundled from the manufacturer of your printer or can be downloaded from their web site.

You're right about CMYK vs rgb colors.

Here's the same traced jpeg image in CMYK (left/top) and sRGB (right/bottom) color spaces




Even visually, there is some difference.

To see the exact difference between the two, you can place them as layers in GIMP (in any order)
and set the blending mode of the top layer to 'Difference'.
You'll get this.





The histogram of the above image shows the difference, indeed.
Total match would result in completely black 'difference' image and flat histogram.