This illustration (figure 1) was created using the free software Inkscape for the creation of a graphical abstract for my Ph.D. The design is copied from actual photography of a Morpho Rethenor butterfly.
A graphical abstract is a visual summary of experimental results, together with its conclusion. The size of the graphical abstract is usually limited and the fewer words appearing on it, the better.
I chose to use Inkscape since it works with vectors. It means that any illustration can be created with as much resolution as needed. It is possible to export the vector images as typical graphics (as .png) or even in a pdf format. As shown in figure 2.
To create this butterfly image, I use the slow (but in my opinion more beautiful) draw tool, which allows me to draw a contour line using points around the butterfly wings and body. It is possible to add as many points as necessary, and the software allows for individual point manipulation (x-y movement, 360-degree angle, smoothing, sharpening…). I use a high-resolution image from the free access Wikipedia image data bank so that I could draw points at small intervals. You can see the points (or “nodes”) in figure 3. Note that the software as an inbuilt tool to “trace” imported illustration, which works relatively well on a simple design, but not as correctly on photography or on illustration with text (which usually you want to get rid off).
The colorization was made easily, using the peak color tool (which allows identifying the closest color available from an original drawing/photography) and the gradient tool, shown in figure 4. It is possible to change multiple aspects of the drawing (contour, the color of contour, the thickness of contour…) and several tools can be used to draw simple geometric shapes (rectangle, ovals…).
I conserved the original Inkscape file (vector format), which means that I can produce a high dpi image of this illustration if need be. I recommend keeping these files, as they can be easily shared with others and .svg files (Inkscape) can be imported within Inkscape.