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Plasma Globe Colors
   

    Right now I use an argon-helium mix, which gives me a bright intense pink color streamers at the terminal, which fade to lavender and then to blue at the glass.  There are a multitude of gases used in making plasma balls, And I shall list a few here.  Some of the pictures are my own, some belong to other people, I have given them credit when they are not mine.

Plasma ball colors:


Helium:      Very bright, I get blue and purple, but differant reports indicate a wide variety of colors (helium spectrum tubes usually show bright yellow-orange as seen below in a digital image taken by Theodore Gray (click on the tube to be taken to his site concerning that element, and the copyright link next to it to go to his periodic table home page, they are very informative pages and worth looking at), but these can vary from plasma ball streamers, and my helium may not be 100% pure (Mr. Gray pointed out to me, that the helium sold in disposable containers is mixed with a substancial amout of oxygen to prevent helium huffers from dying!), also do not trust the colors displayed on this page, digital images do not work correctly for ionized gasses, they are a rough indication only, both of the spectrum tube photos taken by Mr. Gray are in fact the same color.  It works decent at atmospheric pressure in small globes giving fuzzy violet color (a little air in the mix helps, you can even turn a regular helium balloon into a super cheap plasma globe, see middle pictures).  Lower pressures tend to form a purple cloud, and note, helium will not stay in what you put it in, it will eventually leak out even if other gases won't (it is probably the smallest molecule in the universe) it looks cool but it just will not stay (kind of like a bad dog, it keeps running away!) if you have a very well constructed globe, it will stay a while, but not forever.  Please note, I am going to update my helium information as soon as I get some pure helium to work with, I may find the colors are radically differant (yellow maybe?)

helium     grounded helium

atmospheric     grounded

helium letter      helium tube
Copyright 2003 Theodore W Gray
Neon:         Extremely bright, lowest ionization voltage of any gas (except special mixture, see below), it gives blurry red streamers with reddish orange ends, it is favored by plasma globe makers everywhere, and is frequently mixed with other gases.  Plasma Globe photo courtesy of Mark Dunn, Spectrum tube photos courtesy of Theodore Gray.
plasma ball neon 
Mark Dunn

neon letter   neon
Copyright 2003 Theodore W Gray

Argon:        Kind of dim but not to bad if the pressure is right, it has very low ionization voltage, purple-lavender (pink when voltage increases, like at the center, or in a grounded arc) streamers that get darker at the ends (It looks nice, but is dim and a little to blurry for my taste at normal low pressures) it will work extremely well at atmospheric pressure if completely pure, especially in a smaller container, giving bright white lightning streamers (I have pictures of the effect below, when testing with my Tesla coil, the tube bringing the gas in lit up all the way to the tank, which looks cool, but this eventually ruined the tube, but just for experimentation sake, I made a "plasma ball" out of a juice jug using pure argon at atmospheric pressure, and my flyback driver, but note, a smooth terminal will not work, you need a breakout point, unless you have really high voltage, more than a normal flyback can put out).  Low pressures form a maroonish cloud, but it is not as bad as helium, and covering the center electrode would probably help.  One small and interesting note, at a higher pressure (barely low enough to establish an arc), most gases do not create a standard pad at the glass surfaces, but fingers like birds feet, that disappear when the frequency rises from the transistors warming up, just thought you might like to know.  Spectrum tube photos courtesy of Theodore Gray, Argon globe is Mark's as labeled, the other pictures are mine.

argon lightningargon lightning 2argonargon helium plasma globe

Marks argon globe
Mark Dunn

argon letter     argon 
Copyright 2003 Theodore W Gray

The top left and center is pure argon, both free, and grounded to my finger (pretty intense huh?), to the right is low pressure grounded, with a little air contamination, bottom middle is pure argon. Very middle is an Argon globe by Mark Dunn, notice how similar it is to the mine directly above it.  Very bottom are spectrum tubes courtesy of Theodore Gray (note once again the color differance, the left most image I believe to be of a higher pressure, due to it's very blue apperance, as grounded high pressure argon is very blue, not purple like my pictures suggest).

Krypton:     Dimer but cool! gives white ribbony lightning like streamers when used pure (it looks much like atmospheric argon, but dimmer and grayer), but it is usually mixed (because it is expensive, and kind of dim by itself), tends to give gray to green to yellow streams when mixed, and mixing makes it brighter (colors vary a lot with pressure, current, and the other gas if there is one).  It makes the streamers more focused and less fuzzy (goes well with neon).
  Photo courtesy of Mark Dunn, Spectrum tube photos courtesy of Theodore Gray, you can really see here that colors in photographs do not represent real life, these pictures are all pretty much the same color, but they don't look it..
krypton plasma ball
Mark Dunn

krypton letter  krypton
Copyright 2003 Theodore W Gray 

Xenon:       A lot like krypton with it's properties, I don't know what it looks like alone in plasma globes, (spectrum tubes show white to blue, but they often differ from colors in a plasma globe), but it does tend to add blue to everything you mix it with, in spectrum tubes it is blue white as I said, and it is used in xen
on flash bulbs where it is very bright white.  (Save your rubles if you want to buy some, it costs twice as much as krypton where I have seen it available, and I can't afford krypton yet!)  Spectrum tube photos courtesy of Theodore Gray.
xenon letter     xenon
Copyright 2003 Theodore W Gray

Below in this shot of all the noble spectrum tubes together, you can easily compare brightness, seeing that neon is by far the brightest followed by helium, and that once again krypton doesn't look right despite being the same tube in the above photo.
noble rack

Copyright 2003 Theodore W Gray

Radon:   the last of the noble gases, nobody uses this, so I have no idea what it looks like.  This may be because it is radioactive (although radon poisoning comes from the atom lodging in your lung and irradiating it, not from long distance X-rays coming through the walls, so it would probably be harmless trapped in glass) or this may be because it is so large, it is more difficult to ionize, or gives lame colors, or whatever.  It is not really rare, most basements have some, and collecting it is simply a matter of liquefying air from the ground, and distilling it out.  It probably would give extremely focused streamers because the larger nobles seem to do so.

Air:            The most common amongst hobbyists is much dimmer than argon, very deep purple with bluish pink tips, higher pressures form  weak streamers, lower pressures form a cloud much like helium, only dimmer (about this cloud thing, using a covered terminal changes thism, making it more uneven, a higher frequency changes it's properties as well, but it actually looks kind of neat, so you may want the effect!)  Very high ionization voltage is needed (only my good compressor can get it to
ionize with my flyback, whereas with the nobles, my weak compressor will do fine).  It turns your electrode black if it is not covered.

airfree plasma ball     air grounded
Nitrogen:    Said to be everything from orange to gray to purple to pink to bright or dark blue (I didn't try it pure, but air is 70% nitrogen, so it would probably be purpleish in my globe).  Once again spectrum tubes usually show purple, but even they vary with this gas (different pressures and different frequencies produce different colors in any gas, but nitrogen is particularly bad for this, it is a complicated science, one which I may use as a research project some day).


Carbon dioxide:     I didn't try it, and have not found a picture, but is said to be brighter than argon, and very white, it will turn your electrode black worse than air alone.  It is commonly used to make gas discharge lasers, as it emitts a great deal of infra-red frequency light.


Water Vapor:   Extremely high voltage necessary for a good arc (all it does is make a faint purple glow on my discharge terminal), which is a shame because it is a beautiful purple-blue color, but it is to dim to photograph.

Methane, Propane, Hydrogen:  
Don't try these unless you really don't like your face, but hydrogen tends to be blue to red in spectrum tubes or both depending on current and polarity in the case of DC (an example of ionized hydrogen is the sun) I don't know about the others.  Think about it, what do methane, propane, and hydrogen have in common, which would make them less that ideal for sealing them inside a glass globe, and exposing them to an electric flame?)  The reason gas colors vary with voltage current and temperature, is that the dominance of each color in the spectrum of the element changes as voltage current and frequency change.  The light is produced by electrons shifting orbitals and the number of orbitals the shift determins the number of photons they emit, so higher current is brighter.  Does it all make better sense now?


Mercury or metal vapor:   Once again, unless you have serious self-esteem issues, don't try these (too much ultraviolet light mayl blind you) many are pretty much "invisible" (as most of the energy produced is in the ultraviolet or infra-red range), blue at low currents, and green at high currents in the case of mercury (I have some liquid mercury but I am way to scared to try it) aluminum is bright green-blue, but good luck vaporizing and ionizing it with a low current plasma ball electrode! 


    You can observe the different colors of metal plasma by using a high amperage (like a microwave oven transformer supply) Jacobs ladder with rungs constructed of these materials, but once again proceed at your own risk.  I once observed vaporised tungsten in a broken light bulb running under a weak Tesla coil, I have been unable to reproduce this effect until recently, but amongst the regular orange purple plasma filaments (caused by argon nitrogen mixture plasma filaments), there was a thick blue stream between the gap in the filament (it was seeking a ground), which was so difficult to ionize it remained up to a half a second after the coil was shut off.  You can also observe metals vaporised in a (drum roll please...) microwave oven, now is the time to have the concerned parent reading over your shoulder look away, (actually if you are not old enough to buy a new microwave yourself, you should look away as well).  Iron produces orange, copper purple, and aluminum a blue green so intense it burns your eyes, so stick with the Jacobs ladder, that way you can stand to look at it for more than a second.  Actually if you are insane enough to deliberately put something in a microwave that doesn't belong there, please for the love of all that is good, don't leave it on more than a second after plasma forms, or you could damage yourself and the microwave.  Another note of safety if you build one of these suckers, if you ever, and I mean ever, see glass begin to glow green, turn it off immediately, dreaded cathode rays cause this effect if voltage is high enough or pressure is low enough.  Cathode rays are caused by electrons leaping directly from electrode to glass, and when they get there they emit harmful X-rays, which will rearrange the weak hydrogen bonds in your DNA and trust me, you are better off with your DNA where God put it, not where your crazy little device wants it.  If you seriously consider building one of these, you must read my Tesla coil safety page, as most of the information is applicable here as well.

Common mixtures:

Neon-Xenon:
    95% neon with 5% xenon gives the classic pink and blue with focused streamers look as seen in my Radio Shack globe, and this great photo of Mark Dunn's, who is a fellow plasma enthusiast (He made this globe himself, for more information visit http://www.teslaboys.com/Plasma/index.html by clicking here, or click his name below each image).  Also, this picture is a link to a dynamic giff animation given to me by Mr. Dunn (he does not have enough bandwith on his site for this full sized image, but it is worth downloading because it makes a great desktop background or screensaver!)  The rightmost picture is mostly Xenon, with a little neon, same gasses differant proportions, notice how dissimilar they look.

plasma blue plasma globeXenon-neon
Mark Dunn

Neon-Xenon-Krypton:    95% neon with 2.5% xenon and 2.5% krypton is similar to the above except green and orange.  Photo courtesy of Mark Dunn (once again, check out the dynamic image by clicking the picture).

plasma Green plasma globe
Mark Dunn

Argon-Nitrogen:   Purple, with a hint of orange-gray, this is a common mixture in cheap globes, and is also used as a shield gas in light bulbs, container size has to do a lot with perceived color, as seen in these two differant sized light bulbs, the smaller right bulb has a distinct orange appearance often seen in nitrogen spectrum tubes (actually, my camera did not pick up on the orange as it was a frequency it could not "see", but I edited the file to look like the origional, but the purple haze is more bluish than it appears, similar to the left photo).

light bulb plasma globe     nitrogen bulb

Helium-Neon:   Red-orange, and very bright with fuzzy streamers, some sources suggest this combination gives blue and purple at just the right pressure and gas ratio.  They use this mix to make lasers!

Neon-Argon:   The absolutely lowest voltage requirement of any gas with 99.5% neon, .5% argon, fuzzy streamers, it doesn't look that great as it is too fuzzy, and mostly just a cloud reports say, but pressure, and current, and voltage, and frequency are all important, so I will not promote or deny this claim since I haven't seen it myself.

Argon-Helium:   I had to mention this because I use it (althopug hmy helium is not pure, so technically it is Argon-Helium-Oxygen), gives blue-purple pads with pink streamers, tends to have dark and light alternating colored bands in the streamers at lower pressure, and the higher current streamers (grounded ones) have a very distinct orange tint, which cannot be picked up by my digital camera with it's limited optical range (but orange is cool! trust me).

argon helium plasma globe

Argon-Acetic Acid:   Whilst experimenting with a newly constructed globe, I observerd a very interesting effect, at first I believed it was caused by air leaking into my system, until the color radically changed into a color which I have never observed before, a very pale fuzzy purple-white, with bright grounded arcs and dim free flyers, no doubt caused by acetic acid fumes leaking into my globe from RVT silicone, shortly after taking these pictures something in my globe power supply exploded, so I could not take more, note the below picture were taken with a covered discharge terminal, which as I suspected does help make arcs more numerous.

white plasma globe     white2 plasma globe



Neon-Nitrogen-Argon:   Gives orangish white streamers, with hot pink pads, and purple fingers so I am told.

Krypton-Xenon:   Very striking lightning, in a blue color, with a dash of xenon in pure krypton.  Photo courtesy of Mark Dunn.

krypton xenon plasma globe
Mark Dunn

If you know of something I have missed, and can prove its composition, and have a picture, please let me know, I am itching to add onto this section!

Here are my argon and helium tanks, in my very messy basement lab (where else do you put a makeshift lab? upstairs? I don't think so!).  The argon is for welding purposes, and the helium is a disposable party tank for ballons (which is not entirely pure, I will get better helium soon).

gas tanks

One more thing, If you have a spectroscope, you can find out exactly what gasses are inside a plasma gobe, I built a small one out of a CD, a paper plate and some duct tape, which works great for looking at halogen lights and such, but my plasma balls are to dim to view with it, so I'll keep looking for a cheap professional one.


Home, Hobbies, Plasma Ball.

Scott Bogard. 2007