large prism in front of spotlight = rainbow beam?

redberet

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If you put a large prism in front of a spotlight beam, will you get a gradient beam with the colors of the rainbow?
 
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you will get specter of (MH - metal halide lamp) or halogen bulb - gas composition ( so not entire rainbow but specter )

in that way works spectrometers . you have source lamp , then you filter with prism desired wavelength out of specter and then you guide that beam through sample you want to research .

same thing on research of universe - stars ; star light (or sun) you get from telescope through prism and then you get specific spectre ( rainbow ) of elements that burns on sun surface.
 

degarb

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I have been wondering what practical ways of doing this. Practical means to me, a small cheap, durable, lightweight device that can be thrown into a book bag and toted to jobs. . Maybe a prism held in front of smart phone camera, manual white balance snapshot the rainbow and compare to ideal light of same cct.

No luck for last two days googling. White swirl prism photography, cereal box, and 700 dollar spectrometry.
 

degarb

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Diffraction grating won't work for ya?

QSCVPw


https://flic.kr/p/QSCVPw

2017-02-15_02-46-49_zpsuojuv4px.jpg




I see a $20 film. Yes looking for something tangible to buy. Above is a mmish slit in a box with CD inside. Will need to find a manual white balance app. . This will only work with flashlights I own.


BTW, metal halides only come alive above 600 watts. . I don't see a 1000watt mh on your flashlight hit list.
 
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degarb

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My CD in a box tests, aren't really showing me anything yet. A 2012 xml 6500 Kelvin xml rainbow look identical to my 2016 xpl 4300 Kelvin led.

Also, incredibly hard to get light angled and distance consistent.
 

degarb

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1000/mm is what i used to take this pic using my samsung



Now this is what I am talking about! So, you just put the film over (or how far in front?) the camera lens, point at the light and shoot? Could you do several lights, for comparison?

What light is this?
 

degarb

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Found another youtube video,
https://youtu.be/fl42pnUbCCA

They use the clear part of a recordable CD for the diffraction grating film. Is this even possible?

Then, why not just buy a 3 foot section of black abs tubing, and cut it to 12 inches ?

I wonder too, if you also need this foot long chamber and slit, even with diffraction grating film?
 
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FRITZHID

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correct.
i just hold the grating about 6" from camera lens, then tilt/move around till it's where i want it and then shoot. i use no tubes/slits. lol

i'll get some more shots once i get more unpacked from my move. most of my lights are still in the garage.
 
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