Dyes FAQ

General Questions

Can I use any of the dyes listed within foods?

The dyes we offer are not food grade and should therefore not be ingested or put into food. Please remember that you should always consult an MSDS (Material Safety Data Sheet), before attempting anything. MSDS sheets are available on request.




Please could you advise me on what dyes would be suitable for dying plastic like acrylic, perspex and the plastic used for optical lenses. I would be using it for creative purposes and would want it to be relatively fade resistant and have durability.


If you are casting the acrylic you could add the dye to the liquid resin and in this case virtually any of the dyes on our website will do. However, if you are dyeing solid objects this will be slightly more tricky. I always recommend Rhodamine B for plastics, as it is a very tenacious dye, which will stain virtually anything it touches. Rhodamine B is a brilliant fluorescent pink. Acridine orange should also give reasonable results for a fluorescent yellowish orange. Apart from that, the best thing is to buy a small amount and try it.






Fluorescent Dyes



I am trying to put together a stage costume made of white cotton and using some optical brightener so it will glow under UV light. How much cotton will the 25ml bottle of optical brightener treat and what temperature does it need to be mixed at? Does it need boiling, or will too much heat denature the compound?


The 25ml bottle should be enough to treat about five adult size costumes. Dilute it to about five litres (one gallon) and heat it to around 60 - 70°C, immerse for a couple of minutes, wring and hang to dry.





Do you sell fluorescent dyes that can be used to check an automobiles fluids such as oil, water, gas or transmission fluid etc? If so, would the dyes be earth friendly?

We can supply dyes to colour your car's water. The dye you need is fluorescein and we sell it in quantities of 10g or larger quantities on request. For the other fluids we do not currently have anything available, but this is an area we are investigating and it is possible we will supply dyes for this type of application in the near future. Also, if by earth friendly you mean biodegradable, then yes the dyes are earth friendly. Fluorescent dyes such as fluorescein degrades readily in the environment. If by earth friendly you mean natural, then sadly no. All fluorescent dyes are based on petroleum chemistry. We can supply natural dyes such as haematoxylin (logwood) but these are not fluorescent.





I have a leaking pipe somewhere in my basement and I cannot find the where the water is coming from. Is there any way that fluorescent dye could be used to trace it?


Yes, fluorescent dyes such as fluorescein are used to trace cracks in pipes. These dyes are often called tracers. All you need to do is purchase a small amount of the fluorescein or another fluorescent dye and add some to the water via drain or supply etc. It would then be wise to use a UV light source to examine the pipes. The fluorescein will fluoresce bright yellow under UV light revealing where the water is leaking from.



How does the optical brightener work?


Optical brightener is amazing stuff. It works by absorbing light at high frequencies, mostly ultraviolet and then emitting it again at a lower frequency, usually blue.





In what form are the fluorescent dyes? Are they free acids, bases or salts?


All the dyes are in the water soluble form. For fluorescein and bromofluorescein this is the sodium salt, for acridine orange the zinc double salt and for the rhodamines the hydrochloride.





Laser Dyes



Coumarin 1 is an amazing dye, but if I want to use it for laser work, what do I dissolve it in?


Coumarin 1 needs to be dissolved in alcohol for laser work, however if you have difficult obtaining absolute ethanol I understand that a denatured alcohol such as IMS 95% can also be used, or possible isopropyl alcohol.










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Revised: 23rd February 2022