You’ve probably seen it. That colorful gradient strip floating around Facebook or X, usually accompanied by a caption like "Only 1% of people can see 39 colors!" It’s a classic hook. You count the bars, get a number, and suddenly you’re wondering if you have the vision of a hawk or if your eyes are basically broken. But here’s the thing: most versions of the how many colors can you see test you find online are scientifically flawed, even if the underlying biology is fascinating.
Vision is weird.
It’s not just about your eyes; it’s about how your brain interprets signals and, frankly, how good your smartphone screen is. If you’re looking at a low-quality display, you could have the most advanced "tetrachromatic" vision in human history and you’d still see fewer colors because the hardware literally can't render them.
The Viral Myth of the Fourth Cone
Most of these online tests claim to measure whether you are a trichromat (normal), a dichromat (color blind), or a tetrachromat. To understand why this matters, we have to look at the retina. Most humans are born with three types of cone cells. These are our color receptors. They pick up long (red), medium (green), and short (blue) wavelengths. This is why our digital world is built on RGB.
But then there’s the "super vision" theory.
Some researchers, like Dr. Gabriele Jordan from Newcastle University, have spent decades hunting for true tetrachromats. These are people—almost exclusively women—who possess a fourth cone. In theory, this allows them to see a hundred million colors, compared to the one million the rest of us see. It's a massive jump. Yet, when you take a how many colors can you see test on a standard LCD screen, you are limited by the screen's gamut. A standard monitor can only display about 16.7 million colors.
Do you see the problem?
A test displayed on a screen that can only show "Normal" color depth cannot physically prove you see "Super" color depth. It’s like trying to play a 4K video on a 1990s tube TV. The data just isn't there.
The Science of the "Dianne Derval" Test
You might have seen the specific version created by Professor Dianne Derval. It’s a spectrum of purple, blue, green, and yellow.
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If you see fewer than 20 colors, the test suggests you’re a dichromat (like a dog). Between 20 and 32, you’re a trichromat. If you count between 33 and 39, the claim is you’re a tetrachromat.
Honestly, it’s a bit of a stretch.
The image is usually a compressed JPEG. Compression creates "artifacts." These are little digital hiccups where colors smear together. What you are often "counting" isn't your own biological capability, but rather the digital noise and the Mach band effect. The Mach band effect is a psychological phenomenon where the brain exaggerates the contrast between edges of slightly different shades. Your brain creates a line that isn't really there just to help you distinguish shapes.
Why Lighting Changes Everything
Go into your kitchen. Look at a red apple under a bright fluorescent light. Now, take it into a room with warm, yellow "mood" lighting. It’s a different apple.
The how many colors can you see test results can fluctuate wildly based on your environment. Ambient light "pollutes" your perception. If you have a blue-light filter active on your phone because it’s 11:00 PM and you’re trying to wind down, you’ve just manually turned yourself into a temporary dichromat. You’ve neutralized the very wavelengths the test is trying to measure.
Then there’s the age factor. As we get older, the lenses of our eyes naturally yellow. This acts like a permanent Sepia filter. It’s subtle. You don't wake up one day and realize the world looks like an old photograph, but it gradually reduces your sensitivity to the violet and blue end of the spectrum.
Genetic Variation is Real
Despite the flaws in online quizzes, the variation in human color perception is a legitimate scientific frontier.
Color blindness (color vision deficiency) affects about 1 in 12 men and 1 in 200 women. This is usually because one of those three cones is missing or shifting its sensitivity. But the flip side—tetrachromacy—is the real "superpower" everyone wants to claim.
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Genetically, the instructions for our red and green cones are located on the X chromosome. Because women have two X chromosomes, they can carry two different versions of the gene for these cones. If a woman inherits a "standard" red cone gene on one X and a "mutated" version on the other, her brain might develop the circuitry to process that fourth channel.
But even then, having the gene doesn't mean you have the vision.
Dr. Jordan found that many people with the genetic potential for tetrachromacy don't actually "use" it. Their brains treat the fourth signal as "noise" because our world—our clothes, our paints, our screens—is designed for three-cone people. There is no "extra" information in a stop sign for a tetrachromat to see, because the stop sign was painted to look red to a trichromat.
Testing Beyond the Screen
If you really want to know where you stand, you have to move away from the how many colors can you see test found on social media.
- The Farnsworth-Munsell 100 Hue Test: This is the gold standard. It’s not a single image. It involves physically (or digitally, in a controlled setting) arranging 88 caps of color in a smooth gradient. It measures "hue discrimination." If you can do this perfectly, you have elite-level color vision.
- The Ishihara Test: You know this one. It’s the circle made of dots with a number hidden inside. It’s specifically designed to catch red-green color blindness. It’s simple, but it’s effective because it relies on "pseudoisochromatic" plates that confuse the eye if the right receptors aren't firing.
- Anomaloscope: This is a heavy-duty piece of lab equipment. You look through an eyepiece and try to match a solid yellow light by mixing red and green lights. It’s the most precise way to diagnose exactly how your cones are tuned.
What Your "Score" Actually Means
If you took an online test and scored a 39, don't go out and buy a cape just yet. It mostly means you have a high-quality screen (probably an OLED) and you're very good at spotting the "edges" where one digital shade ends and another begins.
It also means you’re likely very sensitive to "contrast."
Contrast sensitivity is often more important for daily life than color depth. It’s what helps you see a grey car through a wall of fog or find a black sock on a dark carpet. People who score high on color tests often have excellent contrast sensitivity, which is a sign of a healthy, well-functioning visual cortex.
The Cultural Side of Color
Here is a curveball: the language you speak affects the colors you see.
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The Himba people of Namibia, for example, have a different way of categorizing colors than English speakers. In some studies, they were able to instantly spot a slightly different shade of green that looked identical to Westerners. Why? Because their language has more specific words for "green" variations.
Your brain is a filter. If you don't have a label for a color, your brain might group it with another one just to save processing power. Taking a how many colors can you see test is as much a test of your vocabulary and mental focus as it is a test of your eyes.
How to Optimize Your Vision Today
You can't change your genetics, but you can definitely improve how you "see."
Start by calibrating your workspace. If you work on a computer, ensure your screen brightness isn't maxed out, which "washes out" subtle hues. Use a neutral grey background on your desktop. Brightly colored wallpapers actually fatigue your cones, making you less sensitive to color throughout the day. This is called "chromatic adaptation."
Also, pay attention to your "blue light" settings. Most modern devices have a "Night Shift" or "Blue Light Filter." While great for sleep, these settings destroy color accuracy. If you’re trying to do anything creative, turn them off and let your eyes adjust to a "Cool" or "D65" white point.
Actionable Steps for Better Color Perception
- Take the Farnsworth-Munsell test on a high-quality, calibrated monitor if you're curious about your actual discrimination levels.
- Check your hardware. If you’re a designer or photographer, invest in a colorimeter (like a Spyder or X-Rite) to ensure your screen is actually showing "true" colors.
- Give your eyes "color breaks." Look out a window at natural greenery for 20 seconds every 20 minutes. Natural light provides the full spectrum, which helps reset your receptors.
- Mind the glare. Reflections on your screen create "veiling glare," which reduces the perceived saturation of colors. Adjust your lighting so no bulbs are reflecting directly in your field of vision.
The how many colors can you see test is a fun distraction, a bit of internet "brain candy." It invites us to wonder if we see the world the same way our neighbor does. The reality is, we don't. Every eye has a slightly different distribution of cones, every brain has a different way of "painting" the internal image, and every screen has its own limits. You see the world through a unique lens—literally.
If you’re genuinely worried about your color vision, skip the memes and see an optometrist. But if you just want to brag to your friends about seeing 40 shades of purple, go ahead and keep counting those bars. Just know that the "test" is more of a digital illusion than a medical diagnosis.
To get the most accurate sense of your vision at home, try viewing these tests in a completely dark room with your screen at 50% brightness. This eliminates external variables and gives your cones the best chance to distinguish those tight gradients without interference from your living room lamp.