Well, I thought about the idea of measuring integrated tint shift. I guess this doesn’t cut it for this use case.
Texas_Ace BLF Calibrated Lumen tube / Sphere No math skills needed - Several spheres still available
As djozz said, yes it will cause a tint shift of some sort, how much and to what degree, I do not have the equipment to test but his results backup my anecdotal evidence.
I have noticed that my high CRI warmer tint lights don’t seem to read as low on this tube with the diffusors as the old style without them. I still round them up but not as much now.
The end point though is that the exact tint hitting the meter really doesn’t matter all that much for what we are doing. This is a cheap, crude and basic version of a very expensive piece of equipment. It was never designed to be perfect, just as good as I could make it for a reasonable price. I have never said otherwise.
Just giving this thread a bump since I still have enough parts for a few spheres.
I just had my video card die on me so trying to replace it but don’t have the funds in the budget for it right now so trying to make a bit extra.
I would be willing to trade for a video card.
Looking for a video card in the RX 480 / RX 580 or better range preferably but an RX 470 / 570 might work as well.
Also on the lookout for a socket 1155 motherboard / a whole computer of ~2500k performance level or better for my Mom.
Don’t have an extra video card now but I plan to upgrade when the Nvidia 7nm comes out, which is about a year from now. I can send you my current one. I’ve been so busy with work and family that I still haven’t had time to get to going through my old harddrives to transfer out useful data. Probably will be sometime next year before I can get to it looking at my current schedule.
No worries at all. Thanks a lot for the offer, when you upgrade I would be interested in that indeed. By then the mod options we have been talking about might be ready.
For now just trying to get something in the system that will at least run all 3 of my monitors and play some games, I am so spoiled I just can’t handle not having multiple monitors anymore lol.
Hi
I am so glad that see you have made this type of LumenTube yourself
But I have some questions that maybe you like to answer me
First : Is anyone else made lumen tubes lnstead of lumen speheres? In Theory I think that you are right, But I just want to know , is this typical or is it your invention? and did you test it and what was the result and accuracy?
Second : In British standard, As I remember, It says that Lumen Sphere’s paiting must have more than 90% reflectivity , And I have searched and found that only paints based on Barit can have that reflection , and paints based on Titan have less than 85% reflectivity , Now I like to know, did you paint inside of yourtube? and Is it isolated from outside?
Third : I want to use this lumen tube idea for Luminaires that are generally much larger than flashlights , Is it possible to change the plan , so it can fit larger lights , and does it result well for all types of luminares? (for example wide beam or narrow beam ones as well)
Fourth : Is it possible to use standard LED Diffusers as diffuser?
Thanks alot for reading.
Texas_Ace did not invent this type of device. They have been built over the years by lots of people, but TA has refined it by adding diffuser panels which really helps to blend the light better. Usually people build lumen tubes or spheres theirself and you get a lot of variations, some of which are not so good. TA made several based on a template so a lot of people could have the same design and get better accuracy. If you plan to build your own, you will want to get a calibration light to test it. You will also need to devise a way to change the opening size if it’s for a flashlight.
It has the bare plastic white interior. No painting is used. You dont have to worry about light getting in from the outside.
The tube design works well for flashlights. It can capture the light and mix it up, integrate it, before it gets to the sensor. I’m not sure what a luminare is, can you explain?
If it’s really big or spreads light from several directions you may have to use a different design, such as a sphere or similar.
You probably can, as long as it spreads the light evenly. TA used a certain type and number of diffusers so the lux meter displayed the lumens with no math involved. This is a nice feature and makes measurements faster.
Late to the party, but I’d like one if still available. Thanks.
TA….you use black tape for tube calibration, right?
Thinking about spectral response errors that all cheap meters have gave me an idea - could we compensate for the errors by callibrating with a carefully chosen paint?
F.e. let’s assume that your luxmeter redponds too strongly to blue light (it likely does). A greyish-yellow paint would absorb more blue than other colours, possilby reducing the error. Am I righ”t?
No need for colour, any white diffusor will remove some blue light due to scattering more than other wavelengths. Light that has gone through the white tube has warmed up too, but will that be the right compensation for a luxmeter with spectral arrors, who knows? 
Yes, this is possible in theory.
Although actually making this work in practice would be very difficult and would need a lot of testing with spectrum analysis.
A filter could also possibly work but same issues with testing and getting it to work properly.
I find just rounding up with warm LED’s and rounding down with CW works good enough.
Scattering is directly proportional to wavelength. LX-1010B which I take as a representative “cheap meter” has many times too high sensitivity for 440 nm. Warming up by going through the pipe? I guess that you mean that pipes are not pure white but slightly yellow right?
What would it take to try to apply a measured correction? I’m not sure but I’ll write down how do I see it.
1. Prepare:
- a tested luxmeter with a known spectral sensitivity curve
- incan bulb
- spectrometer
- 2 integrating tubes
2. Measure the spectral error introduced by the tube.
- (optional) do it at various points of the exit to ensure that the tube integrates well
3. Multiply the spectral errors of luxmeters and the tube. This gives the total error of the tube. Take a negative of that - that’s the ideal corrective colour.
4. Go to paint mixing company. They’ll use software that calculates the optimum blend of a dozen of pigments to produce spectrum that matches your as close as possible
5. Apply the right amount of paint to compensate for the spectral errors (I don’t know how to determine that w/out comparing that tube with a reference)
6. Then - tune with black tape.
7. Apply the same amount of paint to the other tube. Test it.
Yes, it’s a lot of work.
But if it produced improvement that could be blindly applied to other tubes of exactly the same construction, that might push a budget tube correctness up.
Would the effect be significant? I have a hunch that if it was then integrating sphere companies would be doing it already, seems like simple paint + simple filters would be cheaper than the whitest paint + sophisticated filters.
So…I’m not sure if this idea is good at all. And I’m not sure how would one implement it. But the potential improvement seems nice to me.
And maybe someone knows better and can improve the cost and value estimations. 
I expect that most paint pigments affect more than one region of the visible spectrum so that it is impossible to create a combination that produces a tailormade absorption spectrum. It is probably why good luxmeters are so expensive: it takes exotic materials to produce a filter with an exact absorption spectrum.
I was going to say basically the same. While a good idea on paper I have a feeling it would be quite difficult to make it work in practice and would net you other oddities. Such as I foresee different tint lights having the lumen skewed due to the paint absorbing more from one LED then another.
Putting us right back in the situation of having to round the number up or down to account for it.
Don’t get me wrong, it is a good idea and would be cool to test but we are talking dozens of hours of testing with some expensive equipment that most of us do not have at the minimum. That is a lot of time for what amounts to an almost unnoticeable to the human eye change.
Fair enough.
I started a new thread about using the Texas_Ace Lumen tube to post measurements in reply to BLF member requests for specific flashlights.
Here:
Thanks to T_A and all who put in so much work making the “Tube” a thing.
All the Best,
Jeff
If this is already being done some place. Let me know and I’ll edit my POSTs to fix it.
Spamming is not allowed in this forum.
This is not spam, I just recommend what I think is good seller
You signed up to this forum and your very first post was a bunch of links to this company?
How did you even find this topic? It is 6 months old. Are you a flashlight person or did you just search online for people talking about PVC pipe? You realize this looks highly suspicious, right? This is the exact same behavior that a lot of spammers use. I just want you to be aware of that.
JasonWW, just go to one of the links and on top of the page click on "about" the company. That company's name looks very similar to the poster's.
Coincidence?