Affordable Fluorescent Lighting and CRI Explained

How to create affordable fluorescents & avoid the greens.

Commercial fluorescent bulbs and fixtures are affordable, they last a long time, and if you use a 2 or 4 bank fixtures with 4 ft long bulbs, you can get a relatively wide soft source. But they’re not used that much in the film biz. Why is that?

If you said flickering, sorry, that’s just a bad ballast or bulb as well as a heavily used trope in movies. The issue with fluorescents were their green or magenta color spikes due to the type of phosphor coating used, the substance in them that emits light. 

The Greens
Back in the day, if you were shooting in a large space like a department store or supermarket with lots of fluorescents in the ceiling you had an issue because of that color spike. The aesthetic of green tinged lighting to represent a seedy space came from that color, like that awesome opening scene in the first episode of Mr. Robot.

Example of fluorescent lighting that looked white to the eye, but recorded green on film.

How They Corrected the Greens
But if you didn’t want that look, you had to use your own fluorescents light fixtures, for your key and fill, with the same bulbs the location was using in their over heads so all the lighting matched. You then put a correction filter on the camera. The other solution was to put color correction gel tubes or sleeves on every single fluorescent tube in the overhead. 

Then Kino Flo’s came along and changed all that. They’re lightweight, portable and, because of their high current ballasts output more light then commercial fluorescents. But more important, their custom bulbs put out a full spectrum whiter light compared to commercial fluorescent bulbs. They won a technical academy award for it.

Kino Flo 4' 4bank fluorescent light fixture.

And at a price. Today they cost $20 per tube and $1000 and up for the light and ballast. Well worth it but what if you can’t afford them? No problem, because commercially available fluorescent bulbs have gotten better. 

Triphosphor To the Rescue
Not only can you choose from more kelvin temperatures (3000, 3500, 4100, 5000, 6500) but you also have bulbs with different phosphor combinations that create a fuller spectrum white light, referred to as Triphosphor fluorescents. On top of that, we now have a rating system to help us out called CRI.

Example of how CRI (Color Rendering Index) may be displayed on production packaging.

CRI Explained
CRI or Color Rendering Index denotes a light source's ability to show an object’s colors "realistically" in comparison to the standard of either an incandescent light or daylight. The higher the CRI rating, scaled from 0 to 100, the better the light source’s ability to render color properly.  Daylight and incandescent bulbs have a CRI rating of 100. 90 or higher is considered excellent and the standard in the film biz, while 80 to 90 is considered good. Anything below that and you start to get into green-land, like certain cool white bulbs with a CRI of 62. 

Simulated example of what different fluorescent CRI's could do to a recorded image.

Now that the CRI is listed in bulb specs, we can shop wisely. So check your CRI’s. We’ve been using Phillips T8 32 watt 800 series bulbs. They’re good with a rating of 82. Their 900 series are a little more expensive, are in the 90’s but are not carried by our local Homedepot.

Make Your Own Video Fluorescents
Now to make a standard fluorescent fixture work for your video shoots, we suggest a two bulb, 4 foot hanging shop fixture. They cost between $15 and $20. Attach a pigeon plate to the center of the fixture with self tapping three-quarter inch screws. You can get pigeon’s from amazon and they cost around $15. With that pigeon I can now attached the light to a c-stand and rig it anyway I like; vertical, horizontal, angled, pointing down. 

Hardware to modify a shop fluorescent to fit on a c-stand: 3/4" self-tapping screws and a pigeon plate.

Attach a pigeon plate to the back of the fluorescent with 3/4" self-tapping screws. Now you can attach it to any grip stand.

And when I’m not shooting, my fluorescents have another great use. C-stands rock and every household should have one.

Adapt to a Light Stand
But, if you don’t have one, this little baby, the Calumet Universal Umbrella Adapter, is basically a 5/8” to 5/8” pin adapter that sells for around $27US. You can mount your fluorescent on a standard light stand with it, but you’ll probably need a sandbag to prevent it from tipping over.

Universal Umbrella Adapter. This one's sold by Calumet.

The hardware needed to adapt the fluorescent can add up but remember you’re getting affordable fluorescents that are much cheaper then Kino Flo’s with a good color rendering ability.

With advances in fluorescents bulb technology, it’s even easier and more affordable to use them for your video shoots. Stay tuned here for a future video/article where we look at LED tubes and how they may replace fluorescents all together.


Product Links
Fluorescent Fixture
Lithonia Lighting 2 Fluorescent Residential Shop Light
http://amzn.to/2nMGQBv
http://www.homedepot.com/p/Lithonia-Lighting-2-Light-White-T8-Fluorescent-Residential-Shop-Light-1233-RE/202994372

Fluorescent Bulbs
Philips 32W4 ft T8 F32T8/TL850 800 Series Fluorescent Bulb, 5000k, CRI 82
http://amzn.to/2nfj5PU

Philips 32W 4ft T8 F32T8/TL950 900 series Fluorescent Bulb, 5000k, CRI 98
http://www.bulbs.com/product/F32T8-TL950-32W

Pigeon Plates
Avenger F800 3-Inch Baby Wall Plate
http://amzn.to/2nwcLpB

Kupo Baby 3-Inch Wall Plate, Baby 5/8-Inch
http://amzn.to/2nMLTSB

Calumet MF6830 Swivel Universal Umbrella Adapter
http://amzn.to/2nfoWVw

Moonlighting DVDs!
Season 1 & 2
http://amzn.to/2nYCZl5

 

Video Credits

Music & Audio
Fluorescent Bulb Drop_Empty Room_02.wav
filmsndfx
Four foot long fluorescent light bulb dropped from an eight-foot ladder in a large empty room.

The Big Score
https://www.youtube.com/audiolibrary/music

Music Stings from TriuneStore.com
https://triune-store.myshopify.com/collections/music-pack/products/triune-score-bored-identity-action-thriller-music

Stills
Fluorescent lamps still by OiMax
Shinbashi, Tokyo Japan
Old Fluorescent by Dmitry G
Shelves of packaged food inside Ralph's grocery store in Los Angeles by Downtowngal

 

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