Excellent question. And one which made me wonder for quite some time. I finally decided to do something about it.<br><br>Twice now, I have done color and brand/model tests in my bathroom (the biggest room I have that I can shut against window light and all other illumination), reading whatever books I was in the middle of at the time and doing small projects that I could temporarily move into the bathroom.<br><br>Both times, I got an assortment of lightsticks -- Cyalume, Snap Light, Magic Light, Glow Stick and ... Kailume. I did not know about Lite UP at the time, and have since discovered that the technology has been licensed by Coughlan's and certain hardware store chains. I'm sure there are more brands around now than when I did my testing, but I'm content with what I found, so I'm not worried about it.<br><br>For my tests, I unwrapped them all from their foil wrappers and labeled them by brand/model name and by color. (It actually can be confusing, in the dark, four hours into the test, to try to figure out if the one your're holding is the Aqua "Glow Stick" or the Blue "Cyalume" ... or was it one of the "Magic Lights" ... especially if you're tired.)<br><br>I liked the Snap Light design best, for it had both a lanyard hole AND a hook, which I though was more versatile than merely the lanyard hole. I thought the flat sides of the Kailume were better than the round design of all the others, because I figured its chances of rolling away if I dropped it would be less. But, I think the hook is more important. None of them are really cylindrical; they're all slightly conical, widest at the base, and thus would only roll around in circles. :-) The Kailumes were the easiest to tell apart before activation, since the plastic seems to be slightly dyed the color of the light. I think they are designed more for military signalling and marking applications (I got all of mine at an Army/Navy store), and so perhaps they were designed for greater color differentiation, even before activation, so as to help reduce the number of screwups when lives were on the line. I don't know, but the plastic of the Kailumes themselves were much more "colored" than any of the other brands.<br><br>I broke them all at the same time and threw them in the cabinet under the sink, where their light would only barely leak out around the cabinet door, and so allow me to test them apart from each other. One at a time, I took them out and used them as the only illumination in the room. After a while, I would put the one I had out away and take out another one. After I had recorded the results, I ran through them again, then quit for a while.<br><br>They all start quite bright, and it's difficult to decide that any are particularly brighter than the others. The exception, of course, are the High Intensity and the Ultra High Intensity versions, which live up to their names ... for thirty and for five minutes, respectively, before dying quick.<br><br>An hour or so later, I came back and did it again. And again, a bit later. Still later, I ran through it again. The first time, I started in the evening and checked them out for about four hours. In the morning, I checked them all out again, to see how they were doing. The second time, I started in the morning for a couple of hours, and checked them out throughout the evening after I got home from work. I took notes both times I did this. The notes were dry and boring and long and tedious. I no longer have them, but I did record my conclusions, which was all I was really after anyway.<br><br>There was some variance from hour to hour, which, at first, I found fascinating. "Ooh! Last hour, I thought the red was slightly brighter than the orange, but now, I think the orange is slightly brighter than the red. And the blue and white are also interesting ..."<br><br>Yech. That got old fast. Besides, clear winners didn't take long to emerge.<br><br>All the colors seemed to pair up into couples. It was odd. Red and orange kept a neck-in-neck race, as did blue and white. But both blue and white stayed noticeably brighter than either the red or orange.<br><br>In general, I was impressed. They all lasted longer than what was listed on their packages. Of course, this was under controlled humidity and room temperature conditions. How they would react in the open, I cannot know, for I have never used them in Real Life[tm].<br><br>Yellow and green rocked!<br><br>Green held in there with a close tie for a *long* time. It really wasn't until the end of the test that yellow pulled out far ahead of green. Yellow out shines and out lasts all the other colors. Easily. But green does real good for the first twelve hours or so.<br><br>Yellow was still strong enough to read by (though barely) after all the others were long gone.<br><br>Of all the 8 hour duration colors, white was the top performer, but I don't see why you would want that when the yellows (and greens) last 12 hours. Of the two colors available in the High Intensity 30 minute models, the yellow was brighter, but ran out in its designated half-hour. The red lasted quite a bit longer -- BUT, without any rough treatment AT ALL, the red stick being tested sprang a spontaneous leak. In the dark, in an enclosed room, it's an interesting sight to see this tiny needle-thin red glowing stream of liquid squirting out in a small steady stream of light across the room, onto the wall, down to the floor ... Grrrrr. Humph! And it stains. And it stinks! And it did this BOTH TIMES I TESTED! Phooey. I now count red 30 minute light sticks with old chewing gum as Things To Be Avoided. Of course, there is currently only one Ultra High Intensity 5 minute color -- orange -- and it looks *really cool*.<br><br>For what it's worth, I also took the opportunity to test my Kriana "Krill" lamps against the light sticks. Kriana used to have it clearly listed on their website that green was their brightest lamp color. They intentionally put them in order, bright to dim, left to right, in the image at http://www.kriana.com/products.html and said so, but have since removed any text that would indicate that the order in the image has any significance (at least as far as I can see right now). But, given what they themselves suggested this time last year, I chose green as the color for my lamps. However, I needed two 360 degree yellow lamps, one "Standard" the other "Extreme", for a specific purpose, and so was able to compare them to each other and to the green. Neither are as bright as the green, and yes, the "Extreme" models really are significantly brighter in both colors. I have never seen the other colors in action, so cannot attest to their relative brightness levels.<br><br>But even the "Extremes" were far dimmer than ANY of the light sticks.<br><br>Which made me not so enthusiastic about the Krills.<br><br>At first.<br><br>But they did not grow dim.<br><br>At all.<br><br>Which made me change my mind.<br><br>Even about the "Standards".<br><br>After an hour or so, the light sticks all dimmed down until they were close to the levels of the Krill lamps. After that first hour, all of the light sticks sort of "leveled out" at their individual brightness levels, and were almost brighter than the Krills.<br><br>But inevitably, the Krills surpassed the light sticks, or, rather, the light sticks couldn't outlast the Krills. I knew that in my head. It's obvious. But, the emotional impact of having the light sticks slowly dying on me as I stood or sat there alone in the dark ... it gave me an eerie impression of what it might be like for real to be relying on one of them as your sole source of illumination, *knowing* you would soon be without sight in an unfriendly wilderness. It was not a happy feeling. I'll keep at least one Krill in any kit that's got light sticks in it from now on!<br><br>Now to brands. As Doug says on in his evaluation, Cyalume and Snap Light are the serious brands. The others seem to be for play, not work. The Glow Stick and Magic Light burned less bright and not as long. Of course, they were cheaper (after some shopping around), and were marketed as fun novelty items (at least as far as I saw), not as survival equipment, so at least no one is being misinformed. For play, the novelty brands come in even cheaper 4" sticks, so the savings are even greater, if you know anyone who would like them for entertainment and for times when survival is not the issue.<br><br>The Cyalumes and Snap Lights were a bit brighter than the Kailumes.<br><br>At first.<br><br>But, the Kailumes held their brightness longer.<br><br>Significantly longer.<br><br>In fact, they didn't dim nearly as much as the others until much nearer the end. It was really nice. It wasn't like a Ferrari vs. a Yugo, but it was a definite performance improvement.<br><br>I would have no qualms packing Cyalumes *or* Snap Lights. They're great. I would have no problems packing green ones. They're fine. But, given the choice, I would prefer to pack yellow Kailumes. No contest. If you are wondering where to buy Kailumes, you might want to try http://www.google.com/search?hl=en&lr=&safe=off&q=kailume<br>for some possibilities.<br><br>Of course, they have to stay packed in foil. Of course, they have to be protected from crushing or bending, lest they activate prematurely and be useless when you need them. Where you have room, I suggest toothbrush travel holders. (I think I got that idea from someone on this forum.) They're cheap, they're easier to find than cigar tubes and they come in different colors, so you can match them to the color of the light stick inside for quick identification. I use white tubes for my regular yellow (or green) sticks, yellow for my 30 minute High Intensity ones and orange for my 5 minute Ultra High Intensity ones. You can also put a thin lanyard with a clip in the holder tube to attach to the light stick when you take it out of the foil.<br><br>Oh, and there are also some 10 inch, 2 hour models, called SafetyGlow, for traffic situations. The yellow is significantly brighter. During the day, they won't show up worth anything, so stick to road flares. But, at night, they last so much longer, and won't ignite spilled petroleum products, so I love 'em.<br><br>Hope that helps.<br><br>Stay safe.<br><br>