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Old August 20th, 2006, 07:35 PM   #1
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Color temp/exposure question

I have often wondered how it is that in many movies they will film a scene inside next to windows and yet get both the outside and inside to have correct exposure and color temperature. I always thought it was done with filters but then the other day I saw a movie where a person walked from outside into a coffee shop without the color coming out wrong. Do you use lights indoors with the color temperature to match the outside and what is that. I have an xl2 that has 2 built in color temperatures, 3200 k and 5600k. Anyways my question is how do I shoot inside and have the outside still be visible?
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Old August 20th, 2006, 08:03 PM   #2
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1- Sometimes they will build entire sets and shoot in a studio, where the lighting is all controlled.

2- If you are shooting inside:
You can gel or change the lights to be closer to the outside color temperature.

You can gel the windows with ND gel so the windows don't overexpose. There are some budget workarounds to this... John Jackman's book is one source of information on this.

If you reflect the outside light, it should have the right CT provided the reflector reflects light evenly in wavelength (i.e. it is not gold).

3- Cameras can be white balanced manually; this will give you more control and more precise results than the presets. CT varies depending on time of day, pollution + dust, etc.

4- A lot of movies also employ mixed color temperatures... i.e. colored kickers and backlights.
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Old August 22nd, 2006, 11:40 AM   #3
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HMI lights are daylight balanced.

Film is MUCH more forgiving of a broad range of light intensities than video.

Many fluorescent fixtures can be had with daylight or tungsten balanced bulbs.

Glenn mentions ND on windows, color correction filters may also be used on windows, with or without ND, or you can also buy a window-sized gel that includes both color correction and neuteral density.

CTB = color temperature Blue, corrects tungsten to daylight.
CTO = Color Temperature Orange, corrects daylight to tungsten.

The key would be planning... gels to cover lights are inexpensive. ($7 will cover about 4 lights). Gels to cover windows are more expensive. Rental or purchase of HMI lighting is serious money for most indies.
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Old August 22nd, 2006, 09:52 PM   #4
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if i'm shooting a exterior scene that follows a subject indoors .. it is done with a combination of daylight kino flo's and HMI lighting the indoor and what i hope you do NOT see is the 1st AC changing the F stop when i swing the camera around to look into interior (person following camera - somewhere when camera enters doorway camera will let subject pass ) ... if i do not swing camera around then i'll light the interior to approx 2 stop below exterior and i'll do a small f stop change to let the exterior go over 1 -1 1/2 stop ( now interior is 1/2 stop below correct exposure) ... if it is a video release then i'll let exteriors go over 2 stops ....

for interior scenes where you can see out windows i'll have gel on windows ( ND if using 5600K lights indoors or CTO if using tungsten lights .. again i'll let ext go over 1 to 1 1/2 stops .. if it is a video release i'll let the windows go 2-3 stops or more depending on size ....

just for you info - when we shoot night time during the day at locations we usually tent the windows ( build a tent out of black material IE: a 3x4 window may have a 12ft w X12 depth X 10h tent right up against house .. this leaves room to put a light in the tent and have some room to move it around so the camera doesn't see the instrument ) ....
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Old August 28th, 2006, 09:24 PM   #5
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Great stuff. Thanx guys. Where do I buy gels for windows? And where can I buy 5600k balanced lights?
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Old August 29th, 2006, 02:19 PM   #6
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Like the chief said, HMIs or daylight balanced fluos are your best bet. You can buy the latter but you probably want to rent the former. You can get all the gels you need at B&H. Don't get the cheap ones at your local art store! They are not the same.
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Old August 29th, 2006, 09:53 PM   #7
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You can also go to most any "professional-type" photo store and buy incandecent, screw-in bulbs called PhotoFloods that come in 250w and 500w sizes and 3200k and 5600k colors. They fit any household bulb socket and only cost a few dollars. They are the cheapest way to get daylight color temps.
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