Lighting for interviews, documentary

I spent a good part of a day at BH Photo trying to decide on which lights to invest in for documentary interviews. Clearly, there are different kinds of lights to obtain interesting lighting, key, rim, etc.
My biggest question or doubt has to do with the ability to adjust lighting temperatures. Many of the light kits come in daylight balanced only. That sounds well enough. But what if there is a candle, old chandelier, or something in the shot that is much warmer? Is this why they offer the bi-color lights so that one can try to match the temperature to any practical lighting in the shot?
Is the thinking with the bi-color to match the temperature of the incidental light (sun coming through window)? Or if there is some practical light, like a fire or old lamp, to try to match that with the lighting kit?
Or is it often best to embrace the daylight only temperature of a lighting kit, adjust white balance largely to the incidental light created by those daylight settings, allowing the warmer practical light to coexist without making them all line up temperature wise?

Any of those approaches to mixing colors temperatures is valid, depending on the creative goals for the look of the scene and the limitations of available light, equipment, crew and time.

The best way to learn is direct experience, so if you have the ability to either work or even simply volunteer as an extra pair of hands on actual productions, I'd highly recommend doing that before spending your cash on a kit.

A talented gaffer who I've worked with, Alan Steinheimer, wrote an excellent book on lighting that I think you'll find useful:
https://www.amazon.com/Shaping-Light-Video-Age-LEDs/dp/0367819090/

Another useful resource for learning about lighting is:
https://www.hurlbutacademy.com

Art Adam's articles series, Stunning Good Looks, is another excellent resource. Two really useful ones are on fast interview lighting setups (as time can too often be the limiting factor):
https://www.provideocoalition.com/the_simplest_fastest_interview_lighting_setup-ever/
https://www.provideocoalition.com/the-simplest-interview-setup-ever-the-modern-update/

If you're going to invest in LED, might as well go with the adjustable kelvin options over strictly daylight. Though for situations where the greatest possible output is needed, the daylight only models usually deliver the most light output over bi-color.

Newsshooter.com has solid reviews of pretty much every available LED on the market.

Better than reviews is to test them out yourself. If you're located anywhere near a rental house, you can rent a few different lights and spend time testing what works best for you. If you're located far from a rental house, Borrowlenses.com has a variety of lights that will ship to your door.

And, while not an LED light, this is worth a look: https://www.thelightbridge.com

Depending on how you intend to work, investing in grip equipment rather than lights is often the better place to start, especially since LED lighting changes every year. Good grip equipment will last for decades and can be used with any light available at the location, whether that's the sun or lighting units already there. One of the earliest feature docs I shot was on Burgundy winemakers where for some of the trips we were only able to carry grip equipment and lit the locations with either reflected/diffused sunlight or used the halogen work lights that the winemakers all had lying around for working in their cellars.

I like the above advice except regarding volunteering on actual sets. If it's a completely free production for fun, ok, but if it's supposed to be a paid production and you volunteer it really hurts the labour market. The industry where I used to live used volunteers like toilet paper and it became the norm to pay under minimum wage or nothing at all for 12+ hrs in one of they most expensive cities in the USA for very hard physical work (grip). When you work for free it really hurts people who can't afford to do so.

They only kind of free thing I think is okay to do is to observe and provide no labor.

Youtube is your friend. do a search for "interview lighting" and learn, learn, learn. For documentary lighting you first have to ask what kind of documentary and where?

Or is it often best to embrace the daylight only temperature of a lighting kit, adjust white balance largely to the incidental light created by those daylight settings, allowing the warmer practical light to coexist without making them all line up temperature wise?

If your interviews take place indoors – with actual sunlight playing little or no role – or during night exteriors, lit by mixed lighting between daylight- and tungsten/incandescent-balanced sources then it’s generally effective to keep your camera and grading white balance between 3200 and 4400 K.

If your interviews take place outdoors, lit largely by sunlight or overcast skies, then get some warm light sources and use them as fill/rim lights – or use reflectors – and use a camera and grading white balance between 4400 and 5500 K.

Fun fact – color film stock was and continues to be produced as tungsten- (3200 K) or daylight-balanced (5500 K) film negative.

In fact, quite a number of DOPs in the past used tungsten-balanced film to shoot in daylight and used Wratten filters to push it towards 5500 K. I remember reading a forum entry by M. David Mullen where he posits that daylight-balanced negative film started being produced and used widely in cinema only after the mid-80s.

With the rise and dominance of digital, 5600 K started being used widely as a baseline white balance, often even for night exteriors, which is why any white balance towards 3200 K began being seen as “colder”.

My recommendation is: get creative and make bold choices. Try out the white balance for mixed lighting that you develop a preference for, and the one that your clients don’t find oddly conspicuous.

Better than reviews is to test them out yourself. If you're located anywhere near a rental house, you can rent a few different lights and spend time testing what works best for you. If you're located far from a rental house, Borrowlenses.com has a variety of lights that will ship to your door.

Jamie gives great (and experienced) advice as usual.

One note on testing out lights: try buying a secondhand mannequin and use that to experiment with interview lighting. Just a head and upper torso will work; you can mount it on a piece of wood and put it on a chair. Unlike human subjects, mannequins have infinite patience and don't need coffee breaks. You can relax and take all the time you want to try different techniques and placements.

One note on testing out lights: try buying a secondhand mannequin and use that to experiment with interview lighting. Just a head and upper torso will work; you can mount it on a piece of wood and put it on a chair. Unlike human subjects, mannequins have infinite patience and don't need coffee breaks. You can relax and take all the time you want to try different techniques and placements.

That is an excellent tip Brad.

Also useful is a pair of glasses for the mannequin to test lighting for that scenario. Ideally an interview subject who wears glasses will be willing to remove them, but sometimes it's not possible. Testing out key light setups that minimize distracting reflection is time well spent.