Vector art has become the industry standard in many areas of graphic design. As a result, many designers are now faced with the challenge of transforming either self-created or found art works into digital vector format.

This article tackles how to find good public domain source images and transform them into digital vectors.

The search

For some design projects, there might not be time to create an illustration from scratch. Alternately, an illustration style may be required that a designer does not posses the skill for. In these situations it makes sense to search the public domain for usable source images.

Keep in mind that while public domain images are permitted on 99designs with significant modification, stock must always be declared to your client and is not allowed in any logo, illustration or button/icon contests. Be sure to brush up on our stock image and clip art policy here.

When searching the public domain for illustration, there are two important parameters to keep in mind that will help the vector transformation process down the road.


The first parameter to look for is contrast. In the image above, the value of the line work is extremely light in many areas and very close to the value of the background. This will create difficulty in any method of vector transformation.

For instance in using Illustrator’s live trace feature, the line work is merged with the background (shown above). That is why it might be best to move on from this illustration and look for another illustration with higher contrast.


The second parameter to look for is resolution. Sometimes an illustration will have good contrast but the fine line work is lost in pixelation due to the image’s low resolution. In the example above, live trace struggles with the pixelated fine line work and outputs strange looking vector artifacts. Again, it might be best to find another illustration.

The transformation


Classic Film (via Flickr)

There are two main ways to transform an illustration to vector art; the easy way and the hard way. In the former, the computer simply does the work for you using the previously mentioned live trace feature. For a detailed explanation of all the live trace features see Tory’s article here. In the example above, this feature was used quite easily to create a satisfactory result.

The live trace feature doesn’t work on everything and unfortunately it’s fairly common to find an illustration that has poor contrast or low resolution and is simply too good to pass up. This is where a designer must do things the hard way. This method can include a variety of techniques all of which help to achieve a manual trace of the image. Two common techniques are explained below.


The first method is Illustrator’s pen tool to approximate overly pixelated paths (the pathfinder window is also needed to punch out compound paths). This is good for light or overly pixelated illustrations with long straight lines or ellipse segments.

This technique allows a designer to make human decisions regarding pixel approximation that a computer cannot. In the close-up above, the image is too pixelated for the computer to “see” the proper curves, so the pen tool is used to capture the perfect curves of the table.


Illustration: Oliver Hereford

The second technique is to use Illustrator’s blob brush tool in combination with the eraser. In this low resolution image of an Oliver Herford illustration, after about 10 minutes of blob brushing I was able to manually trace the cat’s head in a way that retains the spirit of the illustration without live trace artifacts.


wild cats

Developing an eye for good public domain source images and mastering the art of vector transformation can open worlds for a designer. Also, just because a lot of public domain illustrations are fairly dated doesn’t mean the final design has to be.

Once in vector format, illustrations can be endlessly manipulated, and perhaps the fact that source illustrations are often dated means they should be!

Got any other tips about vectorizing illustrations? Share them in the comments.