April 05, 2022 3 min read

What Colors Glow Under Black Light?

What's that weird purple light in the corner? You're not sure, but it's definitely got your attention. Suddenly, you remember seeing a black light poster for sale, and you realize - that's what it is!

The average white light shines colors all around us, but black light creates an environment where certain colors glow vibrantly. You can use black lights as a party trick to create an exciting and unique atmosphere or as a learning tool to help kids understand the different properties of light.

If you're looking forblack light and don't know what colors will glow under it, you're in luck! This blog post will discuss the different colors that glow under black light. Read on, and you may be surprised by some of the results!

What Colors Glow Under Black Light? | Blog

Why Does a Black Light Make Things Glow?

A black-light emits ultraviolet radiation. This light is invisible to the human eye, but some colors can absorb the radiation and emit visible light. For example, when you see a purple glow under black light, it's because the object is absorbing the ultraviolet radiation and then emitting violet light.

The ability of an object to glow under black light depends on how it absorbs and emits light. Things like paper take in most of the black light that shines on them. At the same time, other objects (like fluorescent materials) emit more visible light when they are "excited" by black light.

White colors usually glow blue, and orange colors shine brighter. 

Note, however, that there are some exceptions to this rule. It's always best to check the black-light color chart if you're unsure about what color will glow.

7 Colors that Glow Under Black Light

Let's look at some of the colors you can see under black lights.


As mentioned earlier, purple is the most common color to glow under black light. It's often associated with mystery and magic, making it perfect for spooky parties or haunted houses.


The right yellow will make your room burst with sunshine! Choose from neon or fluorescently-hued paints and fabrics, which have been treated to be even brighter than usual.


Dark greens do not glow, but lighter shades of green will. Neon green cast an eerie light that's hard to look away from!


Pink is the perfect color to get you in a playful mood. Pink has vibrant shades and special effects like fluorescent light waves that make it glow under black lights!


Orange color glows under black light, but red does not because it doesn't have enough fluorescent additives to make the hue shine brightly. 

Clear substances: 

Water and other transparent substances will also glow under black light, making them perfect for eerie effects like glowing ice or drinks.

In general, any color that does not include fluorescent dyes will look very dark (not glow) under a black light. 

Other Objects that Glow Under Black Lights

In addition to the colors listed above, various other objects also glow when exposed to black light. They include:

  • Rocks: Certain rocks, likefluorite,calcite,opal,scheelite, andsmithsonite, will glow when exposed to black light.

  • Insects: Many insects and spiders fluoresce under black light, including butterflies, dragonflies, and fireflies.

  • Money: Believe it or not, some currency (like the US $20 note) contains black light-sensitive materials that will cause it to glow when exposed to black light. The security strip near the edge of a $20 bill shines bright green when exposed to ultraviolet light.

  • Blood: One of the most famous applications for black lights is detecting bloodstains. The hemoglobin in blood absorbs ultraviolet radiation and emits a distinctive black color. But when the blood is sprayed with luminol or fluorescence, it gives a blue glow. 

  • Teeth: If you're curious about what your teeth look like under black light, a quick trip to the dentist can give you the answer! Dentists use black lights to detect cavities and other dental problems.

  • Urine: With a black light, your urine will glow yellowish green. This glow is because it contains phosphorus which lights up when exposed to oxygen and UV light.

  • Banana: Another cool thing about black lights is that they can reveal hidden spots on bananas! The natural oils in bananas absorb black light and cause them to glow bright blue.  

As you can see, black lights have a lot of potential for spooky fun! Be sure to stock up on black light paint, fabric, and accessories so you can create some eerie effects of your own.