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Black light/glow in the dark


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#1 Arthur Woo

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Posted 25 May 2015 - 10:08 PM

Didn't see a post specifically about this. I'd like to mimic what was done in this music vid. See 0:28-0:53. There are black lights and glow and the dark paint on the dancers/background. 

 

 

A couple of questions:

 

1. Where's the most economical places to get black lights? I see long bulbs, LED panels, etc from a Google search, but like different film light fixtures, I'd imagine they have their plusses/minuses. I'm only using these on one project which has a smallish budget, so not trying to spend a lot.

 

Examples:

 

LED Panel: http://www.proaudios...CFcoXHwodezsAhQ

 

Low powered bulb (not ideal): http://www.google.co...source=3WWRWXGP

 

Strips (not sure if powerful enough): http://www.blackligh...CFdCPHwodL7gAIQ

 

Also I am a little paranoid about these outputting harmful UV - should that be a concern? It looks like the higher intensity ones need protection.

 

2. What's the general output like from a foot candle or f-stop perspective? Ultimately I want to know how many I need to use and i there ones of different intensity. How much do I need to make the backgrounds/talent glow?

 

Any other considerations? Thanks!


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#2 Tristan Noelle

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Posted 27 May 2015 - 10:53 PM

I did quite a bit of testing with black light recently and ended up shooting this teaser video which features some of it.

 

 

1.  The blacklight we used from one 4'x 2 bank kinoflo with 4' T12 bulbs.  We just requested blacklight bulbs with it from the rental house (Wooden Nickel), they we're like $8 a piece in addition to the lamp price.  I used another unit for rimming on the wide two shot which was 2 of those 18" fluorescent fixtures mounted in to a board; I got them from wal-mart and used them for testing before we rented anything. I can't speak for the LED units and whether they put out as much UV or more or less visible light as I never got to test them.  Although I imagine they'd do the job; you can find youtube examples of some of those units. With the kinos I could roughly control output with the barn doors and by switching on/off bulbs, which was handy.

 

On safety:  We had our actress use sunscreen which has the interesting side effect of darkening the skin under black light, which was great for the effect we were going for.  I would recommend it anyway.  In the video you referenced, it appears they did not use sunscreen, hence more visible skin.  Also, there are clear safety glasses you can get at harbor freight or home depot that will block UV light; good for talent between takes and crew.  When you can, turn lights off so people don't look at them unnecessarily as they can cause headaches (at least the Director got one...). 

 

2. Output/exposure:  I didn't measure exposure for what we did.  Black Lights output UV light and some visible light, which has a deep indigo color.  I imagine the only real way to measure output of the UV is by taking a spot meter reading on the material/make-up that is fluorescing.  Different colors and materials will emit different amounts of visible light, so test. 

 

For what it's worth, everything shot in the video was a canon 5DMkIII at 2000iso, mostly around an f/2.  Lit with the 2 4' tubes from the kino, usually around 4 to 6 feet from the model.  We had to get a lot of fluorescing to crush out sections that the visible light hit for the effect we were going for.  it could probably be done with less light.  But more never hurts as it gives you more options.

 

A parting thought:  I found the most saturated color rendition in our fluorescing make-up and clothing happened at very high color temperatures, around 8000K, again option different ones and see what you like.  Our "white" light for the actor was daylight gelled w/ CTB (one or two layers, I can't remember) on a 1x1 LED panel.  I hope this ramble helps you out some.  If I recall anything else pertinent I'll post it.  

 

Tristan


Edited by Tristan Noelle, 27 May 2015 - 10:53 PM.

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#3 Arthur Woo

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Posted 17 June 2015 - 12:41 PM

I did quite a bit of testing with black light recently and ended up shooting this teaser video which features some of it.

 

 

1.  The blacklight we used from one 4'x 2 bank kinoflo with 4' T12 bulbs.  We just requested blacklight bulbs with it from the rental house (Wooden Nickel), they we're like $8 a piece in addition to the lamp price.  I used another unit for rimming on the wide two shot which was 2 of those 18" fluorescent fixtures mounted in to a board; I got them from wal-mart and used them for testing before we rented anything. I can't speak for the LED units and whether they put out as much UV or more or less visible light as I never got to test them.  Although I imagine they'd do the job; you can find youtube examples of some of those units. With the kinos I could roughly control output with the barn doors and by switching on/off bulbs, which was handy.

 

On safety:  We had our actress use sunscreen which has the interesting side effect of darkening the skin under black light, which was great for the effect we were going for.  I would recommend it anyway.  In the video you referenced, it appears they did not use sunscreen, hence more visible skin.  Also, there are clear safety glasses you can get at harbor freight or home depot that will block UV light; good for talent between takes and crew.  When you can, turn lights off so people don't look at them unnecessarily as they can cause headaches (at least the Director got one...). 

 

2. Output/exposure:  I didn't measure exposure for what we did.  Black Lights output UV light and some visible light, which has a deep indigo color.  I imagine the only real way to measure output of the UV is by taking a spot meter reading on the material/make-up that is fluorescing.  Different colors and materials will emit different amounts of visible light, so test. 

 

For what it's worth, everything shot in the video was a canon 5DMkIII at 2000iso, mostly around an f/2.  Lit with the 2 4' tubes from the kino, usually around 4 to 6 feet from the model.  We had to get a lot of fluorescing to crush out sections that the visible light hit for the effect we were going for.  it could probably be done with less light.  But more never hurts as it gives you more options.

 

A parting thought:  I found the most saturated color rendition in our fluorescing make-up and clothing happened at very high color temperatures, around 8000K, again option different ones and see what you like.  Our "white" light for the actor was daylight gelled w/ CTB (one or two layers, I can't remember) on a 1x1 LED panel.  I hope this ramble helps you out some.  If I recall anything else pertinent I'll post it.  

 

Tristan

So helpful, thanks a lot Tristan!


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#4 JD Hartman

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Posted 18 June 2015 - 01:07 PM

I did quite a bit of testing with black light recently and ended up shooting this teaser video which features some of it.

 

On safety:  We had our actress use sunscreen which has the interesting side effect of darkening the skin under black light, which was great for the effect we were going for.  I would recommend it anyway.  In the video you referenced, it appears they did not use sunscreen, hence more visible skin.  Also, there are clear safety glasses you can get at harbor freight or home depot that will block UV light; good for talent between takes and crew.  When you can, turn lights off so people don't look at them unnecessarily as they can cause headaches (at least the Director got one...).

 

Tristan

https://en.wikipedia...iki/Black_light

 

Think you confusing BLB sources with other ultraviolet souces that cause burns, eye damage/cateracts, like tanning bulbs, etc.


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#5 Ed David

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Posted 29 July 2015 - 01:19 PM

I shot a scene with blacklight and man it needs a lot of bulbs to get enough exposure to be suitable at the t stop you want to get to.


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