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diffusing window light


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#1 Fran Kuhn

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Posted 16 March 2006 - 07:16 PM

I'm shooting a test and want to get a white glow from the windows in the room I'm working in. I been able to do this easily by putting a silk on an 8-by or 12-by frame outside the window and waiting for the sun to get behind it, but now I need to accomplish this effect on location at night.

I just tried putting an Arri 2K fresnel behind the silk, but the light produced a lot of specular highlights on the fabric--it's got this ugly, shiny disco look to it. Is there another fabric or diffusion someone can recommend that will produce a smooth glow and is at least large enough to cover an 8x8-foot frame?

Thanks in advance for any suggestions.
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#2 Kevin Zanit

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Posted 16 March 2006 - 08:04 PM

Silk is to thin too put a light directly behind. You could try full grid, but you will still probably have that specular issue, a 2k just doesn?t have enough spread.

You could try bouncing off griff into the diffusion. Or put some curtains over the window.

Here are some examples from a project I did a while ago:

This was shot at night:
Posted Image

And here is some of the setup:
Posted Image
Essentially, the window camera right was way too big to try and blow out with the limited lights I had, so I bounced a 10k off of some griff, and because the curtains were there, it was not specular. I know you were talking about using 2ks, but if your window is that big, you may need multiple 2ks.

The two small windows were some small lighting unit?s bounced into bounce board with opal on the windows.


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#3 Travis Cline

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Posted 16 March 2006 - 08:39 PM

That shot looks really sexy Kevin. I'm just curious if you tried aiming the lights directly at the window with diffusion over them first and didn't like the effect or not. Either way, you ended up with a good result.
I'll have to try that.

Travis

Edited by travisclinedp, 16 March 2006 - 08:40 PM.

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#4 Barry Cheong

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Posted 16 March 2006 - 09:18 PM

How about lining the windows with tracing paper?
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#5 Fran Kuhn

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Posted 16 March 2006 - 10:31 PM

Thanks, Kevin. That's exactly the look I was thinking of. After playing around for a few minutes I kind of figured a 2K was going to be too small. Since I'm limited to residential power on this one, I think I'll have to try the shot in the daytime. Luckily I have about three hours of good light through these windows since they face west.

The tracing paper might look good too. I'll have to get a few small sheets and see what happens.

Thanks again for taking the time to post those pictures. It's really helpful.
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#6 Kevin Zanit

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Posted 17 March 2006 - 02:47 AM

No problem. 1000H looks great on windows, so that?s definitely a good option.

"I'm just curious if you tried aiming the lights directly at the window with diffusion over them first and didn't like the effect or not."

I would have actually liked to have added some more directional light to the scene, but the camera move was a tracking shot forward through the room, and then a reverse all in the same shot with the several actors moving all over the room. They would have really burnt up when they would get real close to the windows, so I decided on a more subtle, real soft light with a slow fall off to help with that.

It looked a bit to perfect to me when we were shooting it, sort of Ikea looking, but it worked for the scene, and the camera move really dictated my lighting choices (along with time and equipment).

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#7 Fran Kuhn

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Posted 17 March 2006 - 04:44 PM

"I'm just curious if you tried aiming the lights directly at the window with diffusion over them first and didn't like the effect or not."


I set the silk up on an 8x8 frame outside and focused the light on it at about a 45-degree angle. The fabric itself has nearly microscopic textures that pick up the light and create a disco-sheen sparkle. It didn't seem to matter where I positioned the light because the fabric texture would still create speculars as though it were a metalflake painted-surface. It's that old angle-of-incidence issue.

In the past this hasn't been so much of a problem because the sun is just so much brighter and it simply blows out every detail.

By the way, sorry for the dumb question, but what is 1000H? Some Roscoe product?

Thanks
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#8 Kevin Zanit

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Posted 17 March 2006 - 05:22 PM

1000H is the commonly used density of tracing paper.

http://www.studiodep...&y=0&field=name

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#9 David Mullen ASC

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Posted 17 March 2006 - 07:12 PM

Silk is best used for diffusing overhead sunlight because it doesn't rattle in a breeze, but as a diffusion for lights, it is mediocre because it does not spread a light evenly, but creates a star-shaped smear, so that's the shape of the source lighting the face, fuzzy & star-shaped. Might be fine if you want some specular quality mixed into the soft light, but otherwise, there are better diffusing materials in various densities, plastic, synthetic, and natural cloth.

For large frames, I usually use different strengths of Grid Cloth. For much lighter diffusing, I'd use something like Half Soft Frost; for really heavy diffusing, I'd use Muslin. Or I'll double-diffuse, putting 4'x4' frames of lighter diffusion in front of the light which then goes through the larger frame of diffusion.

Generally you want your light to fill the diffusion frame for the softest effect, so you'd need to back off the light hitting the frame or use multiple lights to fill the frame. Remember that when using bounce or diffusion frames, the frame becomes the source of light on the subject, not the light hitting the frame.
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#10 Rupe Whiteman

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Posted 17 March 2006 - 08:05 PM

... a bit of a side issue - 'just been reading the Taschen/Kubrick book - he talks about lighting the interior set of the Overlook hotel - remember the beautiful diffuse sunlight coming through the windows? - they used a 100ft long white drape (he doesn't way which material) which was lit with 750 x1000 watt fittings - they literally created a wall of daylight - it looked beautifull and real... and simple.

nb David - what 1000 watt lights do you think he used? This was the early 80s so would they be daylight or tungtens gelled down or corrected in the grade? Interested to know what you think...

Rupe W
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#11 Michael Collier

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Posted 17 March 2006 - 09:27 PM

750?!? 3/4 of a million watts? wow. must have been an impressive sight. you ask what lights he used? without knowing and speaking totaly out of my a.. i would guess they built a rig for that. positioning 750 units would be a pain, and expensive. even using the cheapest lights you are still looking a lot of money. maybe they just got the fixtures for the bulbs and made a grid with them. i read that roger dekins mounted a bunch of 2ks on a piece of aluminum when he couldnt even fit tota lights in place. (big lebowski, scene where rich lebowski reveals the ransom note)

I bet it was a grid of 2ks on plywood or metal or something. but hey im still talking out of my a.. I have always had great luck with natural light, but then again I live in anchorage, so in the summer i get around 20-22 hours of light.
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#12 David Mullen ASC

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Posted 17 March 2006 - 10:12 PM

The AC article (Aug. '80) says that Rosco made a huge welded sheet of plastic diffusion similar to tracing paper (probably 216). The lights were 1K PAR 64 (medium floods). At some point in the story, the windows & glass doors were replaced with glass panes that had Full CTB (blue) gel sandwiched between two panes to make the light coming through to be much bluer.

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#13 Fran Kuhn

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Posted 18 March 2006 - 01:53 PM

.they used a 100ft long white drape (he doesn't way which material) which was lit with 750 x1000 watt fittings - they literally created a wall of daylight - it looked beautifull and real... and simple.
Rupe W

Rupe,

This is what I was thinking about (on a smaller scale) when I did the setup with the 8x8 silk. I got the idea from the Reflections: Twenty-One Cinematographers at Work. On page 40 there’s a window set that Owen Roizman lit with an 8K through a silk for a student workshop. I was surprised when it didn't work that well, but (as David mentioned) the silk fabric is not really appropriate for diffusion. Just when you think you know exactly what you’re doing, you learn something new. I was also surprised because I use the shoot-through-fabric technique all the time, though usually the fabric itself is not in frame.

In the studio one of the most common ways I light sheet metal is to shoot light through a type of sailcloth fabric stretched across a large aluminum frame. One of the studio assistants I work with built several rolling frames, the largest is 30-feet by 16 feet tall. We usually position the frame as close as possible to the subject (usually the side of a car or motorcycle), then position a row of 2Ks at floor level along the back side of the diffusion frame. By flooding/spotting/overlapping the beams from these lights, it's possible to create a very convincing sunset-like glow in the metal. I guess the sailcloth provides a lot more diffuse light than a silk

Anyway, thanks to Kevin, Barry and David for taking the time to reply. I really appreciate it.
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#14 David Mullen ASC

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Posted 18 March 2006 - 02:51 PM

I'd point out regarding "The Shining" that the movie was shot on 100 ASA 5247, and not push-processed either (unlike "Barry Lyndon", "Full Metal Jacket" and "Eyes Wide Shut"). Hence the need for all that light.

Kubrick created the soft top-light dusk effect for the African scenes in "2001" using a huge bank of photographic mushroom globes in the ceiling -- you put enough small lights together in a grid pattern and it starts to behave as a soft light. There is a story that the production of "The Spy Who Loved Me" consulted Kubrick on how to light the giant submarine hanger set (probably Ken Adams asked him) and Kubrick suggested using banks of bulbs again, built into the set as part of the design, which worked.
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#15 Cannonfodder

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Posted 20 March 2006 - 09:35 PM

I'f your really broke try parchment paper, or even a white sheet. These are really poor man ways but if done right they can be effective
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#16 Mark Dunn

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Posted 21 March 2006 - 06:16 AM

That 750k rig certainly was impressive when it burnt down the 'Overlook' set.
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