Optical & Colour Illusions in Design

In the design process, we have to be aware that our eyes can be fooled in many ways. The following is a list of optical and colour illusions we sometimes have to explain to our clients, avoid, or use to the benefit of the design.

The image on the right looks as if there are two colours of green spirals, when in fact the green is exactly the same colour.

Shade of Gray

The two orange dots on the picture, are placed on identical shades of gray (as verified in any image editor). The combination of alternating squares and the shadow casting, interferes with our ability to see the correct color or shade.

Gradient Illusion

The block in the middle of the gradient is actually just a solid colour of gray. This illusion is often in place on websites with gradient backgrounds and solid content blocks.

The Lilac Chaser

The lilac chaser produces 3 different illusions. Stare at the center cross for 30 seconds to see:

1. a gap running around the circle of lilac disks,
2. a green disk running around the circle of lilac disks in place of the gap and
3. the green disk running around on the grey background, with the lilac disks having disappeared in sequence.

The Café Wall Illusion

The café wall illusion creates angled appearance on perfectly straight horizontal lines. This is created by staggering the alternating tiles, moving left and right. The horizontal “mortar” appears to be at an angle.