Applying Knockout Group to a Dynamic Path in Adobe Illustrator

In this week’s free Deke’s Techniques episode, Deke takes the powerful atomic symbol he dynamically drew in Illustrator last week and figures out how to make those electrons hollow so that they show the background behind them.

You might think he’d already done that looking at where we left off last week:

A white atom on a red background

But, in fact, those “hollow” electrons are actually just filled with the background color. Fine if your background is a solid color, but the minute you change it:

A white atom with red electrons on a blue background
And while I think the red electrons look cool, Deke, along with the incomparable Illustrator intellect Mordy Golding, got to talking about the puzzle and, being the guys they are, had to solve it.

The answer was hidden in the Opacity setting of the Appearance panel, where a Knockout Group checkbox resides:

The Appearance panel and Opacity controls

And after a few more adjustments (namely involving reducing the fill opacity settings of the circles that live inside the electrons), we finally arrive at Deke’s desired goal:

A white atom on a blue background

Thing is, Deke and Mordy being the inquisitive Illustrator instructors that they are, gave themselves yet another challenge: how to apply a drop shadow effect to the entire symbol (including the inside of the now hollowed out electrons.

If you’re a member of, Deke’s got an exclusive movie this week in which he (and Mordy) finally figure the puzzle out using Illustrator’s Rasterize effect.

A drop shadow applied to a white atom on a blue background
If you’re not a member of, and you want nothing more than to hear the saga of a couple of Illustrator nerds work out a problem, then you can get a free 10-day trial by heading to

Deke’s Techniques, bringing illumination to Illustrator geeks and those who love them!

Next entry:Blending Multiple Shots to Better Frame a Photo (of an Octopus!)

Previous entry:Make an Atom Symbol with Dynamic Effects in Adobe Illustrator

Be the first to drop some wisdom...