Infinite mirrors, also known as infinity mirrors, are optical illusions created by placing two mirrors parallel to each other. This creates a repeating tunnel of reflections that appears to go on forever. Often, LED lights are placed around the edges to enhance the infinity effect. However, people sometimes notice that the reflections start to take on a green tint after a while. There are a few reasons why infinite mirrors can turn green.
LED Quality
One of the most common reasons for the green tint is the quality of the LED lights used around the infinity mirror. LEDs come in a variety of color temperatures, which refers to the hue of the light. Cooler color temperatures around 5000K-7000K range from white to bluish light, while warmer 3000K-4000K temperatures range from white to yellowish light.
Most infinity mirror kits and DIY projects use cheap LED strip lights sourced from China. These LED strips tend to be on the cooler side in the 6000K-6500K range. While they appear white at first, over time the blue wavelengths in the light cause a green cast to become visible. This effect is exacerbated when the light reflects repeatedly down the infinity tunnel. Higher quality LED strips with better color rendering will prevent this issue.
Viewer Fatigue
Interestingly, viewer fatigue can also cause the green tint. Staring into pulsating infinity mirrors for longer than 10-15 minutes can fatigue the eyes. The rods and cones in the retina become overstimulated and lose sensitivity. This causes an effect called chromatic adaptation where the brain adjusts color perception. Staring at cool blue-tinged LEDs for a while will skew sensitivity away from blue and towards green. When people look away, they may still see green afterimages overlaid on their vision. So paradoxically, the infinite reflections may appear more green simply because the viewer has become adapted to the blue light.
One-Way Mirror Coating
The green cast could also come from the mirror coating itself. Infinity mirrors use one-way mirrors rather than standard glass. These have a special microscopically thin coating that allows light to pass through one way, but reflects it from the other side. This coating is optimized to work best at a 45 degree angle, bending light at a 90 degree angle to achieve the one-way effect.
However, the physics of this coating can shift at other angles. When placed parallel in an infinity tunnel, some wavelengths start to pass straight through rather than reflecting properly. This causes a color shift in the remaining reflected light. The blue and violet wavelengths tend to fail first, leaving mostly yellow and green. Higher quality one-way mirror coatings work better across all angles to prevent this effect.
Background Colors
The color of objects behind the infinity mirror can also influence the reflection color. For example, a black background absorbs most wavelengths of light. But the LEDs in infinity mirrors tend to be weak in red and yellow. So the black absorbs more blue, green, and violet, leaving the reflections to take on a yellow-green dominance.
Meanwhile, white or light colored backgrounds reflect all wavelengths evenly. This provides better color rendering for the full visible spectrum to come through. Dark or colored backgrounds shift the balance based on how much of each wavelength they absorb versus reflect.
Algorithms and Perspective
In some interactive infinity mirror art projects, the colors may shift intentionally based on programming. The embedded LEDs can dynamically change color using algorithms and code. This allows the artist to create different moods and patterns in the infinity tunnel.
The viewer’s angle and perspective can also influence the color they see. Due to the repeating reflections, some wavelengths constructively interfere or cancel out at certain locations. So the color is not necessarily uniform throughout the tunnel. Moving around can reveal different hues of light being enhanced or suppressed based on the interference patterns.
Conclusion
In summary, there are a few key reasons an infinity mirror can gradually take on a green tint:
- Cheap LEDs with unbalanced blue-white light
- Fatigue and chromatic adaptation in the viewer’s eyes
- Imperfect one-way mirror coatings filtering wavelengths
- Absorption of background colors behind the mirror
- Intentional color shifts in interactive art pieces
- Perspective and interference of wavelengths
To avoid the issue, choose high quality LED light strips with good color rendering in the warm white 3000K-4000K range. Also use the best one-way mirror coating possible, placed at the optimal 45 degree angle. With quality components and optimal construction, infinity mirrors can maintain their magical reflections without going green.
| Cause | Explanation | Solution |
|---|---|---|
| LED quality | Cheap LEDs have unbalanced blue-white light that shifts green over time | Use high quality warm white 3000K-4000K LED strips |
| Viewer fatigue | Eyes become fatigued and adapted to blue light, causing green afterimages | Take breaks when viewing and limit sessions to 10-15 minutes |
| Mirror coating | Imperfect coatings fail to reflect blue wavelengths at shallower angles | Use the highest quality one-way mirror coating available |
| Background color | Dark backgrounds absorb more blue/violet, leaving green/yellow to dominate | Use a white or light colored background |
| Artistic intent | Color shifts intentionally programmed to create effects | N/A – it’s part of the desired artistic outcome |
| Perspective | Wavelengths interfere differently based on viewing angle and position | Move around the installation and view from different positions |
Infinite mirrors are an amazing optical illusion that rely on precise alignment of high quality front-surface mirrors. When set up correctly with optimal LED lighting, the reflections should maintain their magical infinity effect without any color distortion. But various factors can cause the tunnel to take on a green cast over time and use. Being aware of these technical reasons allows troubleshooting and prevention to enjoy the mesmerizing illusion as intended.
With careful construction, quality components, and occasional maintenance, infinity mirrors can work visually in homes, events, displays, and art installations; sending viewers into an endless vortex of reflected light.