As answered in this question, transparent bricks are made of PC (polycarbonate) and as listed in this answer and on Brickipedia there are fourteen transparent colors:

40  Transparent (clear) 
41  Transparent Red 
42  Transparent Light Blue  
43  Transparent Blue    
44  Transparent Yellow  
47  Transparent Fluorescent Reddish-Orange (Transparent Dark Orange)    
48  Transparent Green   
49  Transparent Fluorescent Green (Transparent Neon Green)  
111 Transparent Brown (Smoke)   
113 Transparent Medium Reddish-Violet   
126 Transparent Bright Bluish-Violet    
143 Transparent Fluorescent Blue    
182 Transparent Bright Orange   
311 Transparent Bright Green

I am interested in the exact optical properties Transparency and translucency of this colors. How much percentage of light is absorbed? Has anyone measured with a prism which wavelength gets filtered out for each color?

P.S.: Why do I want to know? I want to put different kinds of LEDs in transparent bricks and like to know how the light is influenced. There are LEDs in different colours (light temperature) and one can calculate the luminosity at specific voltage and current. I'd like to calculate the luminosity as modified by the polycarbonate which the LEDs are put into.

  • 5
    If the question is 'How would you measure this?', you would probably be able to get some help from Physics.SE. I would assume you would need a fairly sensitive light sensor to detect the differences in reflected light.
    – Ambo100
    Oct 16, 2012 at 15:56
  • 1
    Do you want an homemade method for doing this at home?
    – pcantin
    Nov 29, 2012 at 3:18
  • @jakob Any more info you could give us? If you answer the questions from Ambo100 and I we could move forward with this question.
    – pcantin
    Dec 7, 2012 at 17:22
  • I don't want to measure this but I'd like to have some numbers, charts, technical specifications etc. to know how light from specific LEDs would be changed.
    – Jakob
    Dec 7, 2012 at 20:05
  • 3
    There are more transparent colours than what's posted in this question. The optical characteristics vary a lot between parts. It depends on the age of the part, its condition, and what kind of part it is. Also the parts are not manufactured to precise optical characteristics, so any two batches of parts of the "same" colour might have different properties. I'm not sure you can get a crib sheet for this, you'd be better off just experimenting with the bricks you get. Jul 5, 2014 at 2:01

1 Answer 1


I have a couple friends in the LEGO company, so I asked one of the guys behind piece creation about this. It turns out that TLC itself doesn't have this information.

The problem is, lab-testing the exact opacity and light absorption depends on certain ideal conditions. These conditions, like for any test, require the material to be identical in every way to the other materials except for the tested variable.

But there is no piece that comes in every color! And even worse, each batch varies slightly from the others. TLC's QA department is good, but not that good.

So while this is certainly a worthy concept to test, you will likely find that your own results will be the most thorough ones you can get. I recommend that you personally do whatever you need to find your answer, and maybe tell us in a comment or on chat what you found!

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.