Increasing light intensity by painting the inside of the bandoors metallic silver
- Thread starter Ken1212
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JPNola
Veteran
Actually, silver or white inner barn doors can increase the amount of light hitting a subject. In the same way that a silver-lined Chimera sans front diffuser results in more luminance on the subject than if the same lighting unit were naked. The reflective inner doors reflect light forward that otherwise would be sent laterally. This is exactly the reason that some of the LED soft light makers produce the light with reflective inner barn doors. They even apply a "stipple" surface so as to add to forward diffraction-
Ck out what occurs in this video at the 6:00 mark after a skirt with reflective inner material is place on a lighting unit. The foot-candles on the subject ( target ) increase:
Reflective doors do not increase the overall output of the lighting unit ( or the overall "volume", to use the OP's term ) but they DO increase the level of light ( volume of light ) on the subject. They redirect scattered light towards the front thus increasing the amount of light in that area compared to no barn doors, compared to less reflective barn doors.
Reflective inner barn doors add light in the same way that a bounce card does. A bounce card doesn't increase the output of the lighting unit, but a bounce card does increase the amount of that lighting unit's output that is striking the subject.
The reflective inner doors ( more reflective ) do increase the size of the source and thus can result in a softer shadow. But only minimally more soft.
The caveat here is that even metal barn doors painted black are fairly reflective. The black inner doors of ARRI fresnels are fairly reflective. When struck by the light of the fresnel to which they are mounted, black-colored barn doors look silver to the eye if not white to the eye. The ability of the black to absorb the light has been overpowered...and the black has become reflective. More reflective than absorptive, that is. The gain from black metal doors to white or silver metal doors is likely minimal in relation to the overall output of the lighting unit. In that sense, it is "gimmicky", imo. A far more significant increase in subject light can be gained simply by moving the lighting unit closer to the subject. If using an LED soft light and wanting as soft a quality of light as possible, the edge of frame should be where you place the unit. Closer to subject = larger in size in relation to that subject = more diffuse nose shadow / softer light.
Big and close. That's the recipe for soft light. If you can't make the unit bigger, move it closer to the subject. Because closer = bigger. Near=larger. Far=smaller. Near, softer. Farther, less soft.
Is this making any sense?
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Yes, thanks for the detailed explanation. I am not sure though I understand (Near, softer. Farther, less soft. ) as I thought near is more spotted or focused and farther is more diffused as by the time light reaches the subject it's wider (of course many ways to diffuse or spot a light)!!!
The reason the question came up, I was interested in a dracast light for both a small studio use and field interviews. right now I am using the lowel dp's. I am pasting a link below to the dracast light. It comes with a barndoor which is important for my studio setup to control light spill when doing green screen and using a black backdrop (my green screen is lit with kino 4' banks). I do like the length of the light as I could use it vertically for full body shots. It comes with black inner barndoors which will help control spill and light direction but thought what if I use metallic spray paint to increase reflective light volume. Frankly I don't understand why most lights don't come with silver inner barndoors since this helps increase reflected light and one can always control more light in different ways but always have a bigger issue for increasing light from a certain fixed position (In my case I already have fixed ceiling mounts that I don't want to reposition) and the studio is small so subject distance is very restricted. Let me also know your input concerning the light below for my type of usage.
https://www.bhphotovideo.com/c/prod...t_drsp_1000b_led1000_series_bi_color_led.html
The reason the question came up, I was interested in a dracast light for both a small studio use and field interviews. right now I am using the lowel dp's. I am pasting a link below to the dracast light. It comes with a barndoor which is important for my studio setup to control light spill when doing green screen and using a black backdrop (my green screen is lit with kino 4' banks). I do like the length of the light as I could use it vertically for full body shots. It comes with black inner barndoors which will help control spill and light direction but thought what if I use metallic spray paint to increase reflective light volume. Frankly I don't understand why most lights don't come with silver inner barndoors since this helps increase reflected light and one can always control more light in different ways but always have a bigger issue for increasing light from a certain fixed position (In my case I already have fixed ceiling mounts that I don't want to reposition) and the studio is small so subject distance is very restricted. Let me also know your input concerning the light below for my type of usage.
https://www.bhphotovideo.com/c/prod...t_drsp_1000b_led1000_series_bi_color_led.html
Liam Hall
Veteran
Light travels in straight lines.
Some basic tips for you:
http://photography-cameras.org/tips/lighting-tips-and-techniques-for-photography
Oh, and the reason most barn doors are black is because they're primary roll is to control spill and scatter. If you need more power, use a more powerful light...
Bern Caughey
Veteran
Given a fixed distance a larger source will produce softer lighting. And as distance increases the source must become proportionately larger to maintain the same diffuseness, or in other words, a 1x1' source placed 1' from a subject will be as soft as 2x2' placed 2' away, or 12x12' placed 12' away.
But the atmosphere is another type of diffusion that's rarely discussed, but can be useful. After about 10', or 12',
a light becomes subtly softer due to the scattering caused by the density of the atmosphere. While this applies to all light, I find it most useful when hard lighting.
But the atmosphere is another type of diffusion that's rarely discussed, but can be useful. After about 10', or 12',
a light becomes subtly softer due to the scattering caused by the density of the atmosphere. While this applies to all light, I find it most useful when hard lighting.
Moseph
Veteran
If this is the case, I certainly wouldn't apply anything reflective to the inside of the barn doors. If you have no space to set a flag and the barn doors and whatever kind of snoots you can build to attach to them are all you have to control your light, you'll want them to function as intended - to cut the light, not to send it in unwanted directions for a marginal increase in intensity.
Don't let people make fun of you - it's a good question and I've done this a lot and tested carefully. My results are it is quite effective with fluorescent fixtures like Divas, 4x4 Kinos and I have a 6 bulb Flo-light that its pretty amazing with ( puts out as much as a Parabeam). I simply bought silver show card, cut it to the size of the doors and attached with clothespins or pony clamps.You need to make sure you angle the doors so they are reflecting the bulbs, but it can boost the effective output of your fixture by 50% (even more with oversize cards) while also increasing the apparent size of your source and so increasing the softness. Looks a bit wanky but its quite effective and I do it a lot. I've always used it with diffusion in front of the unit. I thin the show card would be more effective than paint and a mirror like surface is best as the flo light is already soft. Flo-Lights originally had heavy mirrored doors when they first came out and that's how I got the idea.
Unfortunately I've had absolute no luck wth LEDs I've tried and I've found that the stippled barn doors at least in my lights has no effect whatsoever so I plan to paint mine black so they at least can be more effective for cutting the light. I assume is because LED's are more directional, but maybe it will work with some.
Lenny Levy
Unfortunately I've had absolute no luck wth LEDs I've tried and I've found that the stippled barn doors at least in my lights has no effect whatsoever so I plan to paint mine black so they at least can be more effective for cutting the light. I assume is because LED's are more directional, but maybe it will work with some.
Lenny Levy
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