large prism in front of spotlight = rainbow beam?

[degarb]

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.

What are the dimensions preferable for this film, using your technique? Seems like you need a frame of some invention, dimension. Probably cardboard, glued Popsicle sticks, paint stir sticks, or pictures frame?

Without a frame, you would need a third hand to operate the camera, or tripod - too restrictive.

 

[FRITZHID]

like i said, i just hold the camera in one hand (cell camera) and the film in the other and aim, then shoot. it's really that simple for me.

 

[degarb]

Ok. I also may ask how the quality of the 1000 line grating film spectrum compares to the CD techniques?


I found the simplest construction here,
https://youtu.be/YStZk2zANvk

I knew there had to be uses for these tubes, beyond hamster toys.

The toilet roll tube is shorter than most designs. To me, shorter is preferable for storage, portability, durability, black paint. No one addresses length benefits. Pringle can, comet can, plumbing tubing of various diameter. So why not half inch tubing?

This one clarifies black interior advantages, which seems minimal, https://youtu.be/ZJcl392f8ew

 

[FRITZHID]

much clearer photos thru the film.

 

[degarb]

much clearer photos thru the film.

Do you mean, much clearer photos through the film than a CD grating, or, much clearer photos through the film with inside of tube painted black?

Since your aren't using a tube I will assume you mean the film is clearer than a CD grating.

I am still unsure of how wide and long to order, of the 1000 lines. I would assume 3 to 5 properly dimensioned pieces would last a few decades, stored in basement.

 

[FRITZHID]

correct, film vs. cd

 

[degarb]

How big of a film slide do you recommend? . 3 by 5, 2 by 2 inch?

 

[FRITZHID]

this is what i use

 

[degarb]

this is what i use

https://www.rainbowsymphonystore.com/products/diffraction-slides-1000-line-mm

Unfortunately, they don't sell less than 50 slides at a time.

 

[FRITZHID]

i think thats what i'd bought a while ago. it was less than $10.

 

[degarb]

i think thats what i'd bought a while ago. it was less than $10.

How many fid you get? Amazon has one for $4, with many buyers saying theirs got damaged in shipping. Maybe 3 for $10. Then plenty for $20.

As I am unsure of the practical value, my gut wants three for $5, feeling one for $4 is risky.

Made one last night from a paper towel roll, duct tape, recordable CD, yogurt cup, and black spray paint. . All the leds in my housr look full spectrum. The 6500 Kelvin are heavy in the yellow and green. Obviously, confirmation of bands or spikes on the metal halide, though it too was full spectrum, with stronger red than I expected. This was my 400w warmish probe start....the resolution, lack of tools, make the CD sub useful for evaluation of leds. . Merely confirmation that leds and mh is better than florescent.

 

[FRITZHID]

look on eBay

 

[FRITZHID]

here's some readily avail spectras...

Merc w/phosphor



pure xenon



incan



Ol school floro




Warm white GE Stick




Nichia 219b




Cree warm white XML2

 

[degarb]

here's some readily avail spectras...

Merc w/phosphor



pure xenon



incan



Ol school floro




Warm white GE Stick




Nichia 219b




Cree warm white XML2

Thanks, Fritz.!!!!!!!!

That post does tell me a great deal, about where my CD-R tube is by comparison. Still we need a side by side shot of the same light, by same person, with the film vs. the cdR. The diffraction grating film is better defined, but perhaps, not light years ahead of the CD-R:





These are my images of my 4000K metal halide 400watt probe start, and a 4watt China direct filament circa 2015 purchase.

I took a paper towel cardboard center, duct taped a round yogurt container onto one end, wallpaper bladed a mm slit in bottom (or used old solder iron), tightened up slit with duct tape on either side, duct tape a quarter blank CD on opposite end after pealing off its metal film by exacto knife around edges and duct tape pulling off metal film. Probably, I should melt groove or carve CD before scissoring of a CD R quarter. DVD R failed for me, had to use the recommended cdR on my second try. Duct taped outside for sturdiness and make inside darker. I did use black spray paint on yogurt, not tube, not sure if needed... I built another from a Pringle can, but don't think it long enough to get the definition.

Now, your diffraction grating film bands are a more defined, probably less work getting the picture. The 219 and xml are beautiful. Some of your geometry is very interesting, and I would like to know more. The defined bands in the florescent are spectacular.

So far, have not looked up lines per mm on the cdR spec.

 

[degarb]

http://www.inpharmix.com/jps/CD_spectro.html


Looks like a CD is 600 lines per mm, your diffraction grating film is 1000 lines per mm, a DVD is 1300ish. I am guessing the dvd throws the spectrum too far off to the sides to see in a tube.

Probably more clarity with the film, due to thinness. Maybe the lines are less 3 dimensional, too. Also, 1000 is nearly 2x 600.

Gonna have to try the dvd again. This time using the Pringle can, or Pringle plus pcv for length.

 

[degarb]

This is a CFL CD spectrum. Definitely needs more resolution to evaluate, beyond:"Yeah, the CFL looks a tad more banded than the metal halide. And, spectrometry of the led looks continuous and not that different than the sun or Incan, regale ss of the led temp. " I still am holding out for 3 slides for $5,shipped. Any computer software to evaluate the spectrometry should be in html, not iPhone or dos.

My phone is reading 3000 Kelvin for the CFL, 4500 Kelvin for the metal halide, 6500 for my 500 watt metal halide, which is the sales specifications.