I spent a few hours today experimenting with home made piping gel that glows when displayed under a black light. I've read about this but have yet to come across a specific recipe. I decided to attempt to modify one for homemade piping gel. I took 1/3 cup sugar and whisked it with 1 tbsp cornstarch. To that, I added 1/2 cup of Shasta brand tonic water. I stirred until it came to a boil. I added Electric Green AmeriColor because I wanted a glowing green. To my surprise, under a black light, the color was orange! I tried again, this time using Wilton Sky Blue. That appeared 'clear' under the light. The last thing I tried was putting Wilton Brown into some clear piping gel and that appears Red under the light. Needless to say, I am thoroughly confused. Anyone else out there experimenting?

That's certainly interesting. Did you ever figure it out?

Ok, sugar, corn starch, tonic water, brown color glows red under black light? I have a need for this, just checking your recipe!

keep us posted, Halloween is near could be very usefull.

How about trying Yellow color? The black light gives blue-lavender tint to white, so maybe it shines on yellow it will come out looking green? just a thought... good luck

That sounds pretty easy to mix. I think I'll try it, and experiment with other colors then post those results. It may take a day or two but, want to try it.

Actually, the color "changes" you described make total sense if you think about what a blacklight actually is. (It is NOT a "make stuff glow light").

Regular light, that is light that we can see, is called "white light", but it actually contains all of the colors in the visible spectrum. If you shine white light through a prism, it will break the light into its colored components (our good friend, ROY G BIV). Raindrops can do the same to sunlight, which is how rainbows are formed.

A black light emits electromagnetic radiation that is almost exclusively in the soft near ultraviolet range, and emits very little visible light. The term "black light" is actually a misnomer as almost all of the the light it emits is not actually black, but merely not within the visible spectrum (for humans, that is).

The bulb of a black light is coated in that bluish-purplish color to block nearly all visible light from being emitted by the bulb. The visible light rays that are allowed to escape are red, orange, and yellow (these colors are produced by longer wave lengths which results in this light appearing "dimmer", while green, blue, and violet are produced by shorter wave lengths and are perceived as "brighter").

Additionally, red is not perceived by the rods of the eye, which are the part of the eye that functions best in the dark. The cones of the eye do perceive red, but are less sensitive to light and require 100x the amount of light. This is why the room appears dark or "black" with a black light lamp turned on and a regular lamp turned off.

The reason white light is called white light even though it contains all the visible colors has to do with the way light reacts with objects to produce color. The color we see is actually produced by reflection. The leaves on a tree, for example, appear green in the spring and summer becaus the chlorophyll in them absorbe all of the color rays except for green. The green rays are reflected and thus we perceive the leaves as green. An object that appears white is actually reflecting all 7 of the color rays, while an object that appears black is absorbing all 7 of those rays.

We tend to not think about the light rays outside of the 7 that we can see, but light exists in many many more bands in both directions--beyond red (infrared) and beyond violet (ultra violet). While we humans cannot see these light rays, they still interact with the objects around us.

Thus, when you put the green gel under the lamp, the gel reflected back to you as orange because the blue component of the dye was not reflecting blue because the blue was being blocked by the bulb. The remaining dye components reflected the light that was being emitted by the black light, causing you to see orange. The blue dye appeared clear because there was no blue light to reflect. Brown, which you can create by mixing all 3 of the primary colors, appeared red because the blue was missing.

None of the gels used contained fluorescing compounds, that is, the stuff that "glows" under a black light, which is why they didn't glow. Pretty much ALL fluorescing compounds are toxic, including quinine (in large enough doses). Tonic water contains just enough quinine (0.25-0.5% the prescribed dosage for malaria treatment) to a) give it that nice bitter flavor so essential to a gin and tonic and b) cause it to fluoresce. Just tonic water and piping gel alone should cause the desire effect.

I was thinking maybe yellow too. There is a Buzz Lightyear ride at Disney? where they use blacklight and there is alot of fluourescent green, but i can't recall what color makes that green.

When Mary Maher did this on a cake challenge, I thought she just mixed tonic water with clear piping gel and when they hit the black light it glowed.

didnt Mary use quinine too? or something like that?

Thank you Scoobydid for posting your recipe and results it's very interesting stuff, and thank you Prterrell for explaining how this works, it brought "light" to me for when I experiment with my own colors, thanks again

Wow I love when we get a science class, way to go prterrell

zdebssweetsj and miny - wow! thanks! I half-expected no one to read all of that!

Prterrell, your information was quite useful and thorough. Thanks for taking the time on the subject.

I saw that cake challenge with Mary Maher and I either wasn't paying attention to it at the time or just didn't retain the information. It seemed to me that her stuff 'glowed' green and that was my starting point. Does anyone recall, did she just paint her clear gel onto green fondant perhaps?

All in all, it was a fun day of experimenting. My 8 year old son enjoyed it as well. We'd make up a batch and then run to the closet to see it under the blacklight. He was really getting into it!

I think I need to keep reminding myself that blacklight and glow in the dark are 2 different animals.

What a great explanation!! I can't wait to try this!!

How awesome! I had just figured out that it was removing the blue when I read the "science lesson". LOL Which, I must say, was absolutely brillant!!!! Thank you to everyone for making this thread so amazing!

Sorry if this is duplicate info, but this thread kept showing up on my searches for black light  glowing cake stuff.  This info helped me but I needed something a bit different so I thought I could contribute my findings.

I needed some green glowing slime for my son's cake that will be at a black light lit party place. 

I tried a few things, but here's what worked for me in the end. I made piping gel with gelatin, tonic water and corn syrup. Then I dissolved a few tablets of B complex vitamins in a bit of the gel. It glowed great at this point, but I made it greener with a bit of grocery store liquid blue food coloring.  Unlike some of my other experiments this gel is bright green in regular and black light.

My son picked out this cake design from some inspiration on pinterest. The marshmallow man and car are plastic toys. Hopefully I can post a photo. 

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That cake is simply amazing

So I get this is kind of an old conversation but would anyone have any idea if I could make something like this but in 3D? I read most of this stuff and I'm amazed at what some of you did, I totally have to try this now but I don't know how or if I can. I plan to make a doll cake of Samus Aron for my friends birthday in a couple of months and I'd like to make a little metroid to go with it. When I read all of this I thought it would be even greater if I made it glow in the dark, but I wanted to make it sorta hover next to her by attaching it to a wire. My problem is I don't know what I should make it with. I know that they are clear so can I use clear piping gel to make it, or not?