Grey Glow Illusion (The Glare Effect)

One of the most remarkable illusions to have attracted attention in recent years is the so-called glare effect. Get your dark glasses on!

Glare effects are great to experiment with, using the gradation tool in a graphics package. (I use Photoshop). Here are two figures, one with power specs, and the other a ghost. The latter shows a special phenomenon – a grey glow.

The glare effect has only been written up so far, as far as I know, in recent, seriously technical scientific papers, such as Daniele Zavagno and Giovanni Caputo, The glare effect and the perception of luminosity, Perception 2001, (30) pp 209-222. If that’s for you, you can read a synopsis (or the whole article if your library subscribes) at

If you want to try creating a glare effect, I use the gradation tool in a full version of Photoshop (which I find great for drawing as well as photo image management).  First use the selection marquee tool to define the boundaries of the gradation area.  (Would a detailed tutorial with graphics in a later post be helpful?)

For another picture using the effect, see the ones in my cartoon story with illusions, OpticalOctopus.