Thoughts on branding, design, writing and life by Kevin Potts. Established 2003.

Using Illustrator CS2 To Sharpen Vector Graphics

Illustrator CS2 offers designers some increased functionality in the Appearance and Stroke palettes. Explore just a few of these features as I go over a simple technique for “sharpening” vector illustrations.

Illustrator is kind of like America’s highway system: old and complex, with new stuff piled right on top of the old stuff. Adobe has done a decent job keeping the venerable program up to date, but development is slow, and up until the most recent version, the stroke feature was a neglected piece of functionality. It paled in comparison to Photoshop and Indesign’s capabilities.

But CS2 saw some love given to this oft-neglected feature. Yes, everyone likes to outline text and draw boxes, but strokes provide the opportunity to apply both subtle and drastic enhancements to vector illustrations.

Let’s take the following logo.

first logo version

Its pretty boring, so let’s get stroking. Just to get a handle on the piece, we’ll start with the circle. The midrange colors and gradient are working against us right now, since the unremarkable tones won’t really stand out against anything. We need a strong outline to solidify the logo’s shape, so we start by opening up the Appearance palette (Shift + F6).

illustrator's appearance pallette

The Appearance palette is a powerful menu where you can create multiple fill and stroke paths inside a shape, then edit them individually by reordering, adding effects and adjusting transparency. It almost acts as a traditional layer palette, but on a object level. Layers within a layer, if you will.

As you can see, all we have is the blue gradient fill and a blank stroke path. We click directly on the stroke path, and from the Swatch palette, choose a strong color; in this case, I’ve opted for a deep navy blue. I give it a hefty thickness of 15 pts and leave the default “Align Stroke to Center” setting. I then make sure the stroke layer is behind the fill layer, so only half the stroke shows:

adding a single stroke to circle

This is all fine and dandy, but I don’t really like how the new dark stroke blends with the top of the gradient. Those familiar with Photoshop are probably aware of the Sharpen filter, which helps define the details of a photo by “sharpening” the lines between colored areas. Illustrator doesn’t have anything comparable, but using subtle strokes enables us to emulate the sharpening effect, thus creating the illusion of a more defined graphic.

adding a second stroke

Inside the Appearance palette, we select the stroke and click the “Duplicate Selected Item” icon, second from the right on the bottom. This gives us a new stroke layer. We change the color to white and make the thickness 3pt, then move it above the fill layer. Making sure the new stroke layer is selected, we reduce the transparency to 60%, which reduces the harshness of the white and gives the thinner stroke a more “highlighting” feel. When the logo is reduced to smaller sizes, this small enhancement will help the illustration retain definition.

So the circle is looking pretty good — on to the big “K.” The weak yellow and white gradient is just not cutting it, so we’re going to give the letter a fat, dark blue stroke of 9 pt behind the fill layer like we did with the circle. This nets us a letter with a much stronger weight, and in all fairness we could stop here.

a pretty good logo

The “K” is good, but it could be refined with subtle sharpening enhancements. Unfortunately, this is where we run into two critical Illustrator flaws:

  1. Illustrator does not allow gradients in stroke paths. This is dumb since both Photoshop and InDesign support this. In order to apply a gradient effect, we have to “outline” the stroke, which brings me to …
  2. No matter how you aligned the stroke (middle, inside or outside), Illustrator always outlines a stroke as if it was set to middle alignment. Again, dumb.

Long story short, if we want to apply a gradient, we need to outline, but in order to outline, we need to make sure the stroke is going to look good aligned to the middle of the shape. Fine. We’re tough and we can handle this gaping functionality hole.

So we select our “K,” and in the Appearance palette, add a new white 3 pt stroke above the fill. Making sure the white stroke path is selected, we go to Object > Path > Outline Stroke.

illustrator's gradient pallette

We select our freshly outlined shape and give it a 90-degree gradient. The top end is yellow and the bottom white. Keeping it selected, we change its blending mode (found in the Transparency palette) to “Darken;” this enables the color part of the gradient to come through while the white disappears, giving the illusion of a gradient mask. And since this small gradient is sitting over both the white fill and the heavy blue stroke, it gives a subtle sharpening effect. See below:

outlining the stroke

This sharpens the top of the “K” but leaves the bottom just as it was since the white part of the gradient disappeared from the “Darken” blending mode. We’ll want to add the same sharpening effect to the bottom of the letter, so we select the outlined stroke, hit Edit > Copy, then Edit > Paste in Front. This places an exact duplicate right on top. Without deselecting anything, we open the Gradient palette, change the direction to 270 degrees (the opposite of 90 degrees) and change the yellow color to a deeper orange to better contrast the yellow in the letter’s original gradient fill. You now have the same subtle sharpening on the bottom.

After this work, we have the following. Notice how the final version on the bottom retains better legibility over the “non-sharpened” piece we could have settled on.

a final version of the logo

These sharpening techniques definitely add complexity to a piece of artwork, so be mindful of its final destination. For logos being designed for a golf ball, its probably not a good idea, but for work that will live in 4-color process and the web, adding subtle enhancements can breath new dimensionality into the original shape. And while the techniques I described are good for logos, they are as good (if not better) when applied to icons, where retaining quality at small sizes it critical to the success of the illustration.

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commentary + criticism


wrote the following on Friday February 3, 2006

Great article.

Sr. Designer

wrote the following on Monday February 13, 2006

First of all, you have to know Illustrator is a Powerful vector tool softwares, on the one hand hand, if let you extremely-fine justfy the path or outline into any detail angle or position, on the other hands, because its power software programming, it need a good, clean graphic system to calculate every path, position, color value, ICC or pantone profile into a design, Illustrator can do whatever the author suggest. i.e. make the stroke gradient, but think about it, how many lines and paths will make that gradient show each path or outlines? You can not compared Photoshop with Illustrator, Photoshop programing the graphic as rastor effect, it didn’t calculate the path value or outline inside the text or object, can we call Photoshop dumb because it didn’t provide Pantone value into it’s ICC prfile? It just didn’t do that way of treat color profile, when Illustrator can embedding Pantone but Photoshop can’t, it got different function of each softwares tasks. Illustrator can do what Photoshop can’t, same reason for both, they are most powerful graphic softwares of Adobe flagship products!

ken chan

wrote the following on Thursday February 23, 2006

Great work in the designs and tutorials.




wrote the following on Thursday March 22, 2007

Awesome tutorial. I was able to instantly use everything you mentioned on a last minute logo I’m trying to create. THANKS!!