Manual-Vector Tracing

Manual-Vector Tracing

The most commonly used vector graphic program Adobe Illustrator have an auto-trace feature that allows user any jpg, png, gif, bitmap or any kind of raster image be vector traced by the computer and thus converted into a vector image. The problem with the auto-tracing tool is that it only works as good as the original image is, if user has a low resolution image, this tool is not useful.

Auto-vector tracing tool works by following what it sees as straight lines. How a pixel looks at extreme close magnification. Zoom in close enough on any bitmap, and the user will cease seeing what the image is and see a variety of colored blocks. Each of these blocks is one pixel. Auto-vector tracing tool compares the color values of pixels with adjacent pixels, and if they are relatively the same color, it will interpret that as a solid color. Where there is a dramatic change in pixel hue, such as where a black outline borders a white background. there would be a couple of gray-shaded pixels between solid black and solid white due to anti-aliasing, the auto-trace would interpret this border as a line. The problem is that even though it understands that the perimeter of this dramatic hue change is a border of an object, it cannot produce a single, curved line. It instead creates hundreds of individual anchor points, with straight lines between each.

This tremendously affects the vector file size, as well as how quickly the image can be manipulated. Furthermore, if the image is even the slightest bit pixelated, the auto-trace tool will follow the edges of each pixel, thus creating a pesky "staircase" pattern when lines should be a smooth curve.

This pattern is very undesirable. The only way around this problem is to manually vector trace an image, using the Adobe Illustrator or Corel Draw "Pen tool" to plot and manipulate vector points. when user manually vector trace an image the first thing need to look at is if there's any common shapes. rectangles, circles, ellipses, polygons, etc. If there is a design, it's overall a circle user can make use of it without having to manually draw a circle, just using the circle and ellipse tool. User have to do is manually draw objects tracing around the outline of the illustration. To do that, have two different tools. The "pen tool" and the "curvature pen tool". If the image has lots of straight lines then Adobe would recommend using the pen tool. The pen tool is good for drawing straight lines. But if design is like where there's lots of wavy curved lines and stuff users need to use the curvature pen tool. Because it makes easier to draw curved lines.

That is how professional graphic designers vector trace raster images, that is the recommended printing industry standard. auto-tracing is only as good as the image user is trying to trace. Professional graphic designers perfectly interpret raster images "made up of millions of pixels" and vector trace manually those images into a collection of various vector shapes.