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Window as a backlight


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#1 julien doumenjou

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Posted 19 April 2010 - 01:20 PM

Shooting someone seated in a chair at his desk, can we use the light coming from a window behinf him as a backlight (partly framed) and using an other window (in fact an artificial light with CTB) as a key light ? Is it too tricky or confusing ?

I'm asking because for many reasons, I can't set the shot differently, I can't move the desk nor the camera.
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#2 John Brawley

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Posted 19 April 2010 - 06:26 PM

Shooting someone seated in a chair at his desk, can we use the light coming from a window behinf him as a backlight (partly framed) and using an other window (in fact an artificial light with CTB) as a key light ? Is it too tricky or confusing ?

I'm asking because for many reasons, I can't set the shot differently, I can't move the desk nor the camera.



Your biggest issue with this situation will be balancing the exposure level. If you're suing it as a backlight, there's a fair chance that you'll be looking at or out the window yes ?

In that case, the bigger issue is reducing the glow you'll get from a hot window. It can overwhelm your subject. Instead of backlight you'll get a silhouette.

You can try to balance this out by lifting the key level (and therefore your base exposure) but this generally requires more firepower than your "student" c.com status and use of CTB indicating tungsten lights only indicates you can access.

The other option is to reduce the level coming in. Common techniques for a seemless result include using ND lighting gel cut out and stuck to the window, using ND perspex on the window or large nets or even shade cloth if you're not looking too closely at it.

You can create a key from a non existent window. You have to use your own judgement about weather this looks true and even if you care that it looks true.

I often will not match the CT of the key to a window source either. You might consider 1/2 CTB for better separation and less light lost through your presumably tungsten source. Remember though, that colour saturation decreases as you head towards brighter exposure. Your backlight will tend to look more white than any colour because it will be so bright.

jb
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#3 julien doumenjou

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Posted 19 April 2010 - 11:58 PM

Your biggest issue with this situation will be balancing the exposure level. If you're suing it as a backlight, there's a fair chance that you'll be looking at or out the window yes ?

In that case, the bigger issue is reducing the glow you'll get from a hot window. It can overwhelm your subject. Instead of backlight you'll get a silhouette.

You can try to balance this out by lifting the key level (and therefore your base exposure) but this generally requires more firepower than your "student" c.com status and use of CTB indicating tungsten lights only indicates you can access.

The other option is to reduce the level coming in. Common techniques for a seemless result include using ND lighting gel cut out and stuck to the window, using ND perspex on the window or large nets or even shade cloth if you're not looking too closely at it.

You can create a key from a non existent window. You have to use your own judgement about weather this looks true and even if you care that it looks true.

I often will not match the CT of the key to a window source either. You might consider 1/2 CTB for better separation and less light lost through your presumably tungsten source. Remember though, that colour saturation decreases as you head towards brighter exposure. Your backlight will tend to look more white than any colour because it will be so bright.

jb


Thank you, that was very clear. Unfortunately I read it too late. I shot the scene already, the only thing I did is framing the window as less as possible and put some object in front of it to hide it a little bit. Also, there was a tree just behind that window so I guess that should make it darker as well. Anyway, I'm sure it's not gonna look right. My keylight was an ARRI 300 and it looked very low to me with the CTB
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Aerial Filmworks

Media Blackout - Custom Cables and AKS

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Glidecam

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