How to select the correct glow in the dark pigment

If you would like to make your own glow in the dark paint or object then one of the key requirements is selecting the right glow in the dark pigment for your project. The following article will describe the main key elements of glow in the dark pigments so you can make a more informed choice.

Water Proof v Non Water Proof.

This is one of the key elements you will be looking for in any glow in the dark pigment, is it water proof or not? When a non water proof pigment is exposed to the elements without a protective coating it will suffer moisture degradation and ultimately the entire glow will be lost. Now the drawback of a water proofed pigment is a lesser glow than the same pigment that is not water proofed so the very coating that makes it water proof and protects it from the elements also takes something away from its performance. However unless you are experienced in water proof mediums and know without any doubt that the object you are making has been water proofed by your process then stick with water proofed pigments.

Glow times of Glow in the Dark Pigment

Glow in the dark pigment is NOT all the same and will differ greatly from one manufacturer to another. Now when purchasing pigment it is pointless to go with the sellers words that their glow in the dark pigments are the best in the whole world and no other pigment on the planet will match their after glow times. Any reputable seller of glow in the dark pigment will need to provide the following information on their website for each individual pigment grade.

Now this table shows what you need to look for when comparing pigments and as long as the above information is there it may be provided to you in unique ways by other sellers. What MUST NOT change is the Testing method used to obtain the above information: D65 standard light source, 1000LUX, excitation 10min. All sellers must show that their figures are derived from using this world standard light testing for glow in the dark pigments as above or their data will not be comparable.

The world standard in glow in the dark pigment is gauged in millicandelas per square metre so you can see from my example that the after glow strength of the YG65-LG7 Yellow/Green pigment will be 571 millicandelas at 10 minutes after being removed from its light source. Also the after glow time in minutes at 11890 (198hrs) is the total time that this pigment would glow for if you had it in total darkness and gauged the light output with a specialist photometer not the human eye. The actual visible glow time would be around 12 to 16hrs for both of these pigments with figures like this.

Another important point is to always gauge the performance of a glow pigment from 10minutes or more after it is removed from the light source as the initial brilliance will mean nothing to you in real world applications. Personally I only guage glow pigments at their 60 minute rating and disregard the shorter time spans.

Grades of Glow in the Dark Pigment.

This is also a very important area in selecting a glow in the dark pigment that will be most suited to your particular type of application. Firstly the grade or size of the individual glow in the dark particles are measured in uM or microns which you can think of as a mesh size or screen size. A low size of say 10-20um will not have the same strength and after glow of say 50-65um which in turn will be less than 100-150um however there are certain pro's and cons to each size and it's not a simple as just saying I will use the largest size for the best after glow. As an example if you are making a glow in the dark spray paint you will need a much finer pigment than if you are doing a solid casting.

Suitability of Glow in the Dark Pigment

So you have chosen the type of glow in the dark pigment whether it is water proofed or not and you know the strength as you have compared with multiple sellers charts as seen above and you know the particle size. The final step is to make sure that the after glow intensity and or colour will match your project? Lets say you want to make a product with a super glow you will want the most powerful pigment that you can get. If on the other hand you are making something like a shadow wall you will need a very short lived after glow time so that each time you re-flash the wall with bright light the shadow image updates and scrubs out the previous otherwise you will end up with blurred shadows.

So it's not clear cut, one pigment fits all, it will depend entirely on the type of glow in the dark project that you are working on and the result that you are trying to achieve.