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Backlighting & lighting Night exterior


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#1 Jason Love

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Posted 10 August 2007 - 02:07 PM

Hello, I am a still a humble student so dont know that much..

I know that backlight seperates subject from background but im wondering how important this is. Are there any cases you dont need to worry about the backlight? I ask because i find it hard to imagine where to put the backlight in most cases without seeing it in frame. (especially when panning the camera and such). Limited space inside a room may also cause a problem for positioning the backlight. On a set they probably hang it on the ceiling so no problem to worry about. Also very difficult when the subject is close to the wall.

In particular, I ask for a more specific example: I am shooting a urban drama on HDV. One scene is at night in an outdoor basket ball court enclosed by a high mesh fence. There is no natural source of light that is close, so i was thinking of using a 500w worklight as a practical attached to the top of one of the fences. (ie - a floodlight for the court).

I am wondering where to put a backlight, or whether i need one. Since i dont want it to look too artificial and polished, do i need one? I want it dark and gritty, I will use Collateral and Miami vice as convenient examples, but the subject-matter is closer to La Haine. I dont want to put too much light onto the court, keep it dark, only the people lit.

I've got access to 3-6 250W pro lights with dimmers (to be ashamedly honest, I dont know what type they are). Plus I will have 1 or 2 500w work lights and some methods of diffusion.

There is a fair number of people in this court. So...

Do I need a backlight, first of all?
Where should i put it?
And any general tips on how to light this particular scene?

Any thoughts that can be thrown at this will be greatly apprieciated.

Thankyou
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#2 Kieran Scannell

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Posted 10 August 2007 - 02:43 PM

Jason,

I think your instincts are basically good in augmenting the available light with the work lights, it should look like
it's coming from street lights so maybe you might try gelling them a little yellow or orange for more effect.
Then use your dimmed lights for closer work. I'm actually just wondering if 500w will be enough i think it will if
your shooting hdv. I hope Michael Nash or David Mullen see this they could help you more.
Anyway just try not to over light it, less is more i find with night scenes.

Good luck!

Kieran.
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#3 Michael Nash

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Posted 10 August 2007 - 05:12 PM

You don't always have to use backlight, especially if there are other visual cues to provide separation between your subject and the background. Contrast, color, depth-of-field, movement and so on can help provide visual separation. But for your scene it sounds like you want to keep the background pretty dark, which means the dark fill-side of your subject might start to blend into the background. Visually you not only lose separation, but your subject also becomes more two-dimensional looking (backlighting also helps make objects look more three-dimensional). So some kind of edgelight or backlight on the fill side could help.

Even for a dark scene you'll want to establish light sources somewhere. For a basketball court it would be logical to have one or more lights up on poles, so you could surround the court with maybe four lights near the corners, turning off or diffusing the ones behind camera as you move around to different angles. But there are lots of different ways to visualize this scene!

For some reason I'm thinking of Rodrigo Prieto's work in 8 Mile, which I recall used a lot of soft toplight for night exteriors. It would probably be too difficult to rig for your shoot, but that kind of lighting provides a lot of three-dimensional modeling on faces and adequate separation without resorting to backlight. Often times that's because the darker fill side of the face may be staged against a bit of the background that's also getting toplight.

Which brings me to another point, that a black background usually looks more two-dimensional and smaller on screen, not deeper. Even for a dark, moody scene you often want to light up the background a little bit, for depth and texture to the scene. And nothing says it has to be lit to "key" level; you can exploit dark, murky shadows for texture and separation -- take a look at Deckard's apartment in Blade Runner. The chain-link fence around the court is perfect for texture!

Wally Pfister is really good at using negative fill and no backlight. To create separation he'll stage the actors against hotspots in the BG, even if they only move through it momentarily (it looks especially cool when the negative side is black, and the BG is just slightly lighter but still murky).

screenshot1.jpeg

Of course backlight and edgelight doesn't always have to be motivated by a light source. Sometimes it's logically motivated by the "return" of the keylight (bounce-back from nearby surfaces), or by ambience. You could try using some white foamcore off camera, positioned low and behind the subject, to bounce back light motivated by the return off the court floor. Usually "less is more" with this technique, since all it takes is a kiss of edgelight to be visible yet still look natural.
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#4 Jason Love

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Posted 12 August 2007 - 10:10 AM

Thanks for the help on this one, the tips should be really helpful to me.

Im thinking now of putting up two 500w worklights as the court's own light source. If I put them on opposite sides of the court; this would be a logical place for lights to be on a court? But then im wondering whether there will be too much light filling the court; them worklights do spill out everywhere. Plus the lights would be pretty high up, which is gonna mean subjects might be top-lit. I dont know if this is gonna be an advantage or disadvantage to me. In some angles they would act as a strong backlight, but maybe too high and strong for my key? Although, having them there would mean they are my source of light direction, im not sure if the 250w would do much to suppliment them, in the way of key lighting.

(that probably didnt make much sense, it was kind of stream-of-thought...sorry)

I read somewhere that the backlight has to be 2 stops stronger than the key to have any effect... is this nonsense?

Thanks for the image of Ray Liotta too. It looks amazing without any backlight, or any sign of fill either. What film is that from?

I would like to get some of the texture in the fence lit in the background, im supposing it only needs a little bit though...

Thanks again.
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#5 Kieran Scannell

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Posted 12 August 2007 - 03:08 PM

Jason,

The Ratio of key to back light is essentially a matter of taste, how do you want it to look? but 2 stops is a good rule of thumb
that should give you a nice hard edge on faces. Top light is inevitable when your lights are mounted that high but it should look
quite natural on a basketball court at night. You might also try a "wet down" making the ground reflect the lights and also
your actors, might give it another dimension, you could use buckets of water from a friendly resident in the area! people are
generally eager to help a film crew.

Good luck.

Kieran.
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#6 Michael Nash

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Posted 13 August 2007 - 08:33 PM

I read somewhere that the backlight has to be 2 stops stronger than the key to have any effect... is this nonsense?


Nonsense. Does this backlight look it's two stops over?

screenshot.jpeg

(This and the other still are from a new DVD release called Slow Burn)

How bright a backlight needs to be depends both on the reflectance of the subject and the contrast against the background (and the contrast against the fill side of the subject, in this case). Since in this pic the background is black and the fill side is black, it takes very little backlight to show up on camera. If the subject was even shinier (like if it was raining in the scene and Ray's hair and skin were wet), the backlight would be reflected even brighter. In a scene with more brightly lit subjects and backgrounds (like a day exterior) you'd need a backlight to be quite a bit brighter, for it to have any contrast against the background. A backlight that's two stops over key is a very bright backlight, even for a day scene. You don't have to have anything nearly that bright unless that's just how you want it to look.

Since you're shooting on HDV you can easily set the brightness of the backlight by eye, looking at the monitor. In fact this works for film too, you just get experience knowing what "looks right" and you don't always have to meter it.

The subtle backlight in the picture is what I was suggesting when I said use some foamcore to return the keylight. This is just a gentle "kiss" of light, enough to be seen and create separation without drawing attention to itself as a light source. Imagine what this shot would look like if the backlight had been two stops brighter than the key!

If you mount your lights on top of the fence and aim them at the center of the court, they will be somewhere between a top light and a sidelight. It won't be toplight unless the action takes place right against the fence, right under the lights.

Using only two lights on opposite sides of the court will give you a pretty flat contrast ratio, and the scene won't look very dramatic or dark. You might be better off putting one light to the side of frame and the other farther back as an edge/backlight, so that it hits the dark fill side of the faces. Then move your lights around when you switch to different camera angles, so that you always model your subjects with a visible key side, fill side, and edge- or back-light.
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#7 Jason Love

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Posted 19 August 2007 - 03:44 PM

The subtle backlight in the picture is what I was suggesting when I said use some foamcore to return the keylight. This is just a gentle "kiss" of light, enough to be seen and create separation without drawing attention to itself as a light source. Imagine what this shot would look like if the backlight had been two stops brighter than the key!


Thanks,

How would you position the reflector behind the subject? I presume it is quite low to the ground below the subject's waist as to not be in frame... I cant imagine it being off-frame to the side... this would be too far away and not to the back enough.

So how would one put a reflector behind the subject? Is it just a low C-stand? I cant imagine a grip guy holding it, lol. But i dont have C-stands available. so what are the other solutions?

Also, I'm not sure if reflecting natural light on an overcast day-time is enough light to create a backlighting. However, if its gonna be raining too then I cant use lights. Well, I cant really use lights in a particular location because its outside a Hospital, so I dont want to disturb too much with generators and such. Working with natural light on an overcast day... is back-reflecting possible? Or resort to another method of background seperation on this case?

Thankyou once again.
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#8 Michael Nash

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Posted 21 August 2007 - 04:57 AM

Where and how you place reflectors depends on the shot. For wider shots you may not be able to get a bounce card close enough, and for tighter shots you can work the card in a little closer to the subject. If you're framing a closeup, there's plenty of room to place the bounce board just off frame. And "grip guys" hand-hold bounce boards all the time!

Lighting on an overcast day is completely different from lighting at night. Backlighting doesn't usually look very natural in overcast conditions since the natural light is rather soft and "toppy." You're usually better off using other visual cues to create the illusion of depth, like shallow depth-of-field and staging your subjects against backgrounds that provide contrast. It sometimes helps to use a little "negative fill" on your subjects; using large black frames to block ambient light on one side of your subject so that the light "wraps" or "models" your subjects with a little more contrast, making them look more three-dimesional.
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#9 Jason Love

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Posted 23 August 2007 - 08:49 AM

Where and how you place reflectors depends on the shot. For wider shots you may not be able to get a bounce card close enough, and for tighter shots you can work the card in a little closer to the subject. If you're framing a closeup, there's plenty of room to place the bounce board just off frame. And "grip guys" hand-hold bounce boards all the time!

Lighting on an overcast day is completely different from lighting at night. Backlighting doesn't usually look very natural in overcast conditions since the natural light is rather soft and "toppy." You're usually better off using other visual cues to create the illusion of depth, like shallow depth-of-field and staging your subjects against backgrounds that provide contrast. It sometimes helps to use a little "negative fill" on your subjects; using large black frames to block ambient light on one side of your subject so that the light "wraps" or "models" your subjects with a little more contrast, making them look more three-dimesional.



Yeah you are right sorry, hand holding bounce boards is the easiest solution. I guess i just assumed my crew would be too lazy. lol.
I've done 3 scenes in overcast light already now. One of them in an estate turned out a good result using bounceboards on close-ups. Looking back on some footage I now realise that bouncing the light up to the front of the face would be more benifitial on overcast days. I was just worried that overcast light would produce flat results.

Thanks for the tips
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Media Blackout - Custom Cables and AKS

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Gamma Ray Digital Inc

Glidecam

Aerial Filmworks

Willys Widgets