Colour Illusions: How Designers Use Colour to Trick the Eye and Transform Spaces
- Katie Lane Botteselle
- Jul 30
- 4 min read
Colour is hands-down one of the most powerful tools an interior designer can play with.
It can totally change how we see a space, mess with our sense of size and distance, stir up emotions, and even trick our brains into believing something that isn’t really there.
Think making a cramped room feel huge or giving a chilly space a warm, cozy vibe—all with just the right color choices.
In this post, we’re diving into the magic of colour illusions: how they work, the psychology behind them, and how interior designers use colours and tricks to completely transform a space without moving a single wall.
The Psychology of Colour Perception
To understand these illusions, you first need to know how we see colour.
Our perception isn’t fixed—it’s influenced by lighting, surrounding shades, textures, and even what we expect to see.
That’s why one colour can look totally different depending on what’s next to it or the kind of light hitting it.
Designers lean into this flexibility, using it to make rooms feel deeper, taller, brighter, cozier—you name it.
It’s a way of steering how we move through and experience a space without changing the physical structure at all.
How Designers use Colour to make Spaces Feel Bigger or Smaller
One of the oldest tricks in the book: using colour to change a room’s size.
Light colours—think whites, pastels, and soft neutrals—bounce light around, instantly opening up a room and making it feel airy.
That’s why small apartments often go light and bright.
Dark colours do the opposite. They absorb light, pulling walls inward and creating a more intimate vibe. Perfect for making a large room feel cozy—but if you go too dark in a tiny space, it can feel a bit boxed in.
Design tip: Paint the ceiling lighter than the walls to make a room feel taller. Want a bit of drama instead? Add a darker accent wall to visually create depth.
Warm vs. Cool Colours: The Push and Pull of Colour
Colours have temperature, and it changes how we see space.
Warm colours (reds, oranges, yellows) seem to move toward you, creating a snug feeling.
Cool colours (blues, greens, purples) visually pull back, making walls feel further away.
Design tip: Got a narrow hallway? Cool colours can make it feel wider. Want to balance a long room? Paint the far wall a warm shade to visually “bring it closer.”
Using Contrast and Value for Depth
Value refers to how light or dark a colour is.
By playing with contrasting values—light against dark—designers can create a sense of depth and dimension. This technique is frequently used in both interiors and graphic design.
For instance, placing a dark-coloured piece of furniture against a light-coloured wall can create striking contrast, making the object pop and enhancing the three-dimensional feel of the space.
Design trick: In open-plan layouts, designers may use darker tones in the background and lighter tones in the foreground to create the illusion of depth and guide the viewer's eye through the space.
Simultaneous Contrast: How Colours Influence Each Other
Here’s where things get fun.
A colour can look different depending on what’s next to it. That’s simultaneous contrast in action.
Ever notice how a bold sofa seems to shift colour when you change the wall paint? Or how a grey swatch can look bluish beside orange? Designers play with this to make colours feel more vibrant or toned down.
Design tip: To make a colour pop, place it next to its complementary shade—like a red pillow on a green sofa. Instant wow factor.
Creating Flow Without Walls
Colour can subtly divide an open space into different “zones.”
In retail, bold colours pull your attention to certain displays. In homes, changing paint colours can mark out a cozy reading nook, a dining area, or a workspace—all without building physical dividers.
Design tip: Try painting the back wall of a bookshelf or alcove in a contrasting colour to make it feel like a feature of its own.
How Finish Changes Perception
It’s not just which colour you pick—it’s also how shiny it is.
Glossy finishes bounce more light, making a room feel brighter and a colour more intense.
Matte finishes soften everything, soaking up light and creating a calmer vibe.
Design tip: Low-light rooms benefit from semi-gloss or satin finishes—they help light travel further and make spaces feel less cramped.
The Afterimage Effect: Optical Colour Residue
This one’s more of a party trick than a common design move.
Stare at a red wall for a bit, then look at a white surface—you’ll briefly see green.
That’s the afterimage effect, caused by your eyes overloading on one colour.
Some modern art installations even use this phenomenon to create interactive, mind-bending experiences.
Designing with Intent
Color illusions aren’t just neat visual tricks.
They’re intentional, psychology-backed strategies that let designers shape how a space feels.
Great design isn’t about filling a room with stuff—it’s about shaping an experience.
With clever colour choices, designers can stretch or shrink space, warm it up, cool it down, and guide attention without ever lifting a hammer.
Next time you walk into a room and it just feels right—bigger, cozier, or perfectly balanced—chances are, colour is working its quiet magic in the background.
If you’re ready to see how thoughtful design can transform your own space, Katie Lane Interiors would love to help.
Take a look at some of Katie Lane Interiors recent projects for inspiration and imagine what we could create together.
And when you’re ready to start your own transformation, head over to our Contact page to get in touch—we’d love to hear about your vision.
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