Trigalight™ Lamps Information

COOL Science Information Page

Trigalight™ Lamps

We suggest you read all the information here before purchasing Trigalight™ Lamps.
We are more than happy to answer any other questions you may have before you purchase - please use the Contact Us form on our website.

What are they?

The Trigalight™ lamp is a gaseous Tritium light source or GTLS developed in Switzerland and is designed to be used as an aid to finding items in dimly lit situations. The Trigalight™ requires no batteries, neither does it need charging from sunlight or any other light source before it will work - it is a completely self-contained power source.

How does a Trigalight™ work?

The Trigalight™ is composed of a laser sealed borosilicate glass tube which has a special phosphor coating on its inner surface and has been filled with a small amount of Tritium gas. As the Tritium decays the beta particles emitted by its nuclei strike the tube’s phosphor coating causing it to emit visible light. By varying the type and combination of phosphors used it is possible to create tubes which emit different colours.

The excitation of phosphors by electrons (beta particles) used in the GTLS is the same principle used to create the television picture in the old cathode ray tube televisions, only in the case of the GTLS the electrons are provided in the form of beta rays by the disintegration of the Tritium nuclei.

Tritium has a half-life of a little over 12 years so as long as it is not damaged the Trigalight™ will emit light for many years.
Please note that descriptions you may have seen on other websites DO NOT apply here, there are NO manufacturers guarantees for the life-span of a Trigalight™ inspite of what other websites may claim!

How safe is a Trigalight™?

As the electrons produced by the gaseous Tritium are so low in energy, they are unable to breach a sheet of paper or to penetrate human skin.

Trigalight™ lamps are NOT toys and are NOT suitable for children

Can a Trigalight™ be damaged or stop glowing?

Yes, a Trigalight™ lamp is made of glass so it can be damaged and will stop glowing - so care must be taken when handling
Breakage of the GLASS Trigalight™ is the only thing that will cause it to suddenly stop glowing and this is NOT covered by the manufacturers warranty - so please understand that if you break the lamp we will NOT give you a refund or a replacement.

We can only supply the Trigalight™ lamps and cannot do anything about how you, the customer uses them. If, for example you are intending to make or provide a case for the Trigalight™ and it is not properly designed the lamp can be damaged. If the case has no cushioning around the seals or is too tight a fit, it can also damage the Trigalight™ as can the use of adhesives and resins. We strongly recommend against using any sort of glass-glue as these contract on setting and will literally pull the lamp apart! A properly designed Trigalight™ case should have, for example, silicone pads to support the lamp to reduce shock from impact and protect against thermal expansion and contraction.

What colours are there and how bright are they?

This is a list of the colours we can supply (subject to availability) and an explanation of the perceived brightness:
Green, Yellow, White, Orange, Ice Blue, Red, Pink, Purple, Deep Blue

Do all of the colours appear to be the same brightness?

The simple answer is NO they do not, and the biggest reason for that is the human eye! It does not have a linear response to colours and this is why we perceive some colours to be brighter than others. The light coming from a green laser will appear to us to be very much brighter than the light coming from a red laser with the same output power; so with the Trigalight™ lamps there is quite a big difference between how you will perceive the colours to which the eye is most sensitive and to which the eye is least sensitive.

So; which Trigalight™ will look the brightest, and which the dimmest?

By far the brightest looking Trigalight™ is the Green and the dimmest the Deep Blue; this is because Green is roughly centre of the human eyes visible spectrum, as you approach the upper and lower limits sensitivity falls off sharply. If you consider the Green as the brightest perceived then Deep Blue will only appear to be about 15% as bright as the Green, Yellow is close to Green and is seen as about 80% as bright as the Green.

The list of colours shown above was compiled by us when looking at the Trigalight™ lamps in the dark as what we perceived the order of brightness to be, from brightest (left)  to dimmest (right); and although there is a large difference between the brightest and the dimmest, between some of the colours it was difficult to agree on exactly the order they should be arranged in, if you do some searching on the Internet you can find numerous lists of perceived brightness, some agree with ours and some differ slightly.

The important thing is: if the brightness IS important then you should select Green or Yellow - if it’s not then pick a colour you like but expect it to NOT appear as bright.

What kind of brightness can actually be expected?

As stated above, Trigalight™ lamps are designed to be used as an aid to finding items in dimly lit situations. - they are NOT torches so they will NOT light up the room, or give you something to sit and read by.

How bright they will actually appear to you will also depend on how well dark-adjusted your eyes have become, for example: if you go from a brightly lit situation into the dark and look at your Trigalight™ it won’t appear anywhere near as bright as it would if you’d been sitting in the dark for say 10 minutes and then looked at it, it takes time for your eyes to adjust to a darkened room.

To summarise, the brightness and colour contrast of the Trigalight™ lamps can seem very different depending on ambient lighting conditions and of course a person’s perception of colour is very subjective.

How much should I rely on the colours and apparent brightness of the images I can see on the website?

This question highlights a problem you will always come across when trying to buy something from the Internet based on how it looks; in this case the colour and how bright it appears.

If you look at the apparent brightness of the different colours on the website they all probably look about the same brightness, why is this? Firstly, when taking the photographs the camera was set to a bulb (or timed exposure) setting so as to obtain an image that was bright enough to be useful. Secondly, cameras, whether film or digital based have a different response to colour sensitivity than the human eye; it is impossible to show how bright these will actually appear by showing you a photograph on a computer screen.

As for the colour it is impossible to give you an accurate representation of how you will actually see the colour, a full explanation of why would be very long but is basically as a result of the colour gamut’s of the different technologies used in bringing you the colours over the internet versus the human eye; so use the colours shown in the images as a rough guide only.

Some of the colours actually look quite similar to each other in real life, the Deep Blue is supposed to be a rough approximation of the colour of an old black-light lamp (blue with a hint of purple) and looks quite similar when compared to the Purple Trigalight™ which may not be apparent on the images, where it appears more blue. So as we said, please use the images as a rough guide only.

For a brief peek at this fascinating subject see Colour Perception in the COOL Science Blog.


We stock various sizes of Trigalight™ lamps and the dimensions can be found on the individual product pages.

Intellectual Property Notice

All of the content in these pages is the intellectual property of COOL Science

Any redistribution or reproduction of part or all of the contents in any form is prohibited other than the following:

  • you may print or download to a local hard disk extracts for your personal and non-commercial use only
  • you may copy the content to individual third parties for their personal use, but only if you acknowledge the website as the source of the material
  • YOU MAY NOT, except with our express written permission, distribute or commercially exploit the content. Nor may you transmit it or store it in any other website or other form of electronic retrieval system.

External Websites Disclaimer

Whilst we endeavour to ensure that any references to external websites are accurate and relevant to the subject discussed in these pages, they are only provided for the purpose of further information the reader may wish to explore.
Their presence is not meant to imply that COOL Science endorses or guarantees either the information found therein, or the organisations, companies or persons who own those websites.
We can take no responsibility for the maintenance or contents of external websites.

All information contained within these pages may be subject to change without notice.