The user should try all three filters, and observe the different types of output for different types of input images.
But you do need to come to terms with 3D space and controls to use them. In the image below I use the 'Draw freehand lines' tool to draw a shape corresponding to the face.
Quick question: Also, how do you "Make a new file with only the color you need. The representation is a bit more approximate and rough, but the drawing is much simpler and easier to edit. In gimp, I also tried the Color to Alpha, it worked for the white background..
This is the most important step because there is a compromise between the cleanness of the image and the with of the resulting edges. No autotracer can do that.
Canny as a way of quickly finding isoclines of similar contrast. I could just close them off and try the paint bucket tool, or I could show you another method for coloring. Both of them should now show the dotted outline and arrow handles.
In order to best understand this, I'd strongly suggest taking the time to watch a few videos on vector drawing in Inkscape so you can thoroughly perceive the nature of vector illustration in this "classic" methodology.
My PDF is not a vector file.
I am really outside of my comfort zone here... I'm a writer, web programmer, composer, designer, and video editor with an interest in all things digital media. Now you can use the various sliders to pick a colour you like.