Manual vectorization with soft color blendsHere is an example of a recent vectorization from photo to vector (raster to vector). This drawing was for screen printing and, for this particular project, it didn't have to be drawn using only vectors. In addition to drawing with vectors, some vector graphics programs also have tools that allow you to use pixel-based, raster (non-vector) elements such as soft color blends & shading/highlights. A graphic that is created with a vector drawing program but also includes pixel-based smooth color blends and soft shading is not a 100% vector graphic, or a true vector graphic; it contains both raster and vector elements. See Raster vs Vector
Photographs are raster graphics made with pixels: a multitude of different color pixels create a realistic image. Vector graphics are drawings made with objects: lines and curves that create shapes. When a photo is vectorized, it means a drawing of the photo is being made and, in most cases, the new vector graphic will be considerably different as you will see in some of the examples below.
Manual vectorization without color/shading blends - 100% true vectorCertain processes such as specialty printing (printing on bottles, pens), plotters, vinyl-cut signs, engraving, and other processes require 100% vectors without soft color blends or shading.
Below is a photo to vector conversion with no gradient shading or blends. The original raster and the new vector graphic look considerably different. This project was for engraving which required black and white line art, no gray-scale mid tones. More on Grayscale vs Line Art
Color "blending" may be created using only vectors by adding multiple objects and gradually changing the color tone of each consecutive object. The more color objects you draw, the smoother the transition between the colors will be. Achieving a smooth transition may be time consuming if drawing is done manually.
Automated vectorization - Tracing tool
A photograph or an image with color blends and soft shading may be vectorized using only vectors and still maintain a strong resemblance to the original. A large amount of color/shade objects may be needed. Rather than drawing each object by hand, the Trace tool in vector graphics program can automate this process. The tracing tool may or may not render acceptable results. In my experience, the same processes that require 100% vector art also require simplified vector graphics with limited amount of color/objects, and accuracy that is often only achieved by drawing manually. See more examples of manual vector conversion vs automated vectorization
Manual vectorization 100% true vector "line art" with color
Below is a raster to vector conversion using only vectors and no pixel elements. The original heart is made of a multitude of different color pixels. The blend of different color pixels gives a 3-D appearance with highlights and shadows. Redrawing the image with single color vector objects instead, produces a considerably different image that looks "flat". Another example of how different an image will look when you take away the color blends.
I am hoping the examples above will show how photographs and color-blend-full images may change in appearance when vectorized. See more vector conversions here.
Images were vectorized by vector-conversions.com. Logos and photographs are the property of their respective owners.
I welcome comments and corrections!