Ok, you got me curious. What is your "Lumen Tube" project?
a poorish man's way of isolating the light from a bulb, or flashlight from outside sources and measure it's output in lumen. (not calibrated)
i won't try to explain the mechanics as i would probably get it wrong.
got the idea from Matt Smith on youtube.
he first shows an integrating sphere made out of a cooler, later in the video a lumen tube.
i think he
might be incorrect using foot candles though.
Texas_Ace over on BudgetLightForum AKA BLF also has built many lumen tubes.
https://budgetlightforum.com/node/60100the tubes are somewhat like an 'integrating sphere' but more reliable at defusing the focused beams or 'throwers' of flashlights than the styrofoam cooler method.
if you search for lumen tube and see a pair of lungs, disregard that. lol
i tried finding a good article on the theory, mechanics etc but found WAY to many bot made articles.
i want to be able to compare lumen:watt ratios for LED light bulbs before and after modifying them.
with either cutting 1 of 2 parallel resistors on current limiting type PCBs of plastic dome bulbs, or swapping it's value.
also putting a captive dropper in line with the AC of brighter 'non-dimable' glass bulb LED lights.
both inspired by our beloved BigClive.
contemplating getting a UNI-T cheapo thermal imaging camera (UTI690A) as many LED bulbs seem to run well over 60°C by my finger-o-meter.
would also be handy for many other things.
also want to see efficiency curves for LED flashlights at different LED driver currents and types to show diminishing results in both directions.
diminishing efficiency on the low side, diminishing output on the high side.
if i were just doing bulbs, i would probably had done a cooler box.
ok, this reply has gone on for way too long.