Preparing Artwork for Printing and Cutting

I generally find there are several distinct parts to creating artwork: scanning or otherwise acquiring images that form the basis of your work, and then actually drawing (and this may include tracing the images and scans you have). I will discuss all these separately.

Choosing a Drawing Program and Other Software

Generally speaking, you need tools for editing vector graphics, and I strongly urge you to stay away from working with raster (bitmap) graphics (working with scanned images being an exception). Vector graphics is a particular approach to computer graphics where images are created using basic geometric shapes (lines, curves, etc.). Vector graphic images can be scaled freely without any loss of precision, unlike raster images.

I use Adobe Illustrator exclusively when creating artwork. It is without a doubt the best and most sophisticated vector graphics drawing program available today. It is, however, expensive since you need a subscription to Adobe's "Creative Cloud" service. There are good alternatives, however. I believe the best substitute is CorelDRAW, but it is also expensive as it, like Illustrator, is really built for professional illustrators. The best free alternative is Inkscape, and there are other free options as well. Things to look for are good support for exact measurements and good color management (the latter you need if you are printing decals).

Other software you may need are editing tools for raster (bitmap) graphics. Usually intended for photo-editing, these can also be used to edit scanned images.

Drawing

As I implied earlier, this is not a tutorial for computer-based illustration, but let me at least explain the basics of how vector graphic images are created. Generally, images are a combination of lines, other basic geometric shapes (such as circles, rectangles, etc.), and free-form (but mathematically constrained) curves called Bézier curves.

Drawing using basic shapes is simple, but seldom gets you all the way to the result you need, and for this reason it is a good idea to really practice the use of Bézier curves; it is actually easier than the impression you get if you read the linked Wikipedia article.

Once you master the basics of creating images using the shapes described above, other features in drawing programs will come to your aid in managing the complexity of drawings. These features include grouping (collecting parts of your image to be treated as a single object) and layering (placing different parts of your illustration on different "layers" which can be locked or hidden on demand).

A Bézier curve in Adobe Illustrator.

I often also create color profiles of the aircraft I am building, in anticipation of producing decals. Below is once such profile, created using Adobe Illustrator. I gave this image to a colleague of mine whose father flew this particular aircraft. I am now building a model of this, and the artwork I created forms the basis for creating decals and masks for the model.

Scanning

It is a good idea to have access to a decent flatbed scanner. I like to use one that has a resolution at least 1200 dpi (dots-per-inch). When you scan, and then import the resulting image (in JPEG or some other bitmap format), how large that image is depends on the scanner software and the graphics software. The best scenario is that your graphics software knows the exact resolution you used in your scanner (older versions of Illustrator did this), or it assumes some "default" resolution (newer versions of Illustrator use 72 dpi). In the latter case you have to scale the image to be able to later create artwork exactly in the same size as what you scanned. So let’s say I scan in 1200 dpi, and Illustrator decides to use 72 dpi, I then have to scale the scanned image to 6% of its original size (72/1200 = 0.06). It is a good idea to get comfortable with scale conversions and ratios.

Tracing: Combining Scanning and Drawing

Scanned images can be used to create new, more precise vector graphic images. I think of this process like the digital equivalent of tracing an image on paper. Adobe Illustrator lets you place a scanned image at a "layer" below the one on which you are drawing, and also allows the image to be "dimmed" as if you were tracing on partially translucent paper like vellum. I usually dim the image to be traced anywhere between 20% and 50%, depending on what kind of colors it has, and lock the layer so that I can freely draw on the layer on top of it without moving or otherwise disturbing the scanned image. The images below illustrate this process.

Scanned image placed on the canvas in Adobe Illustrator. This was originally scanned from the decal sheet for the A-Model 1/72nd scale Gee Bee R-1.

Original layer locked and dimmed to 20%, and now drawing on a new layer on top of the old one: tracing using a Bézier curve, for the purpose of cutting a mask.

Adobe Illustrator also has an automatic tracing function, and it can sometimes be used, but the resulting image typically needs to be "cleaned up" (by reducing the number of "anchors" or control points, etc.). I seldom use it, instead opting for the manual process, particularly if I am tracing somethign simple like registration letters or tactical numbers.

After you have traced everything you need, the layer with the scanned image can be deleted, leaving just your new artwork. This can then be further edited, and if you are making decals, colors can be added. I usually save the final artwork in PDF format (if I am making decals) or in SVG format (if I am making masks).

---