Simulating Daylight from a dark set

Hywel Phillips · April 6, 2013

Hi All,

I could do with some advice on simulating daylight on a dark set, on a low budget feature I am DoP'ing. Please forgive the cross posting (I posted this on REDUser as well).

The film is set in the 1930's, set mainly in offices with a small cast. These are going to be built as sets on a makeshift soundstage (a large barn).

I've not lit interiors for daylight starting from a dark set before. Usually I shoot on location and use my lighting rig to supplement daylight or light night interiors. So the tricky bit for me is doing some sort of simulation of daylight through the office windows.

I haven't seen the barn yet, the sets haven't been designed let alone built, so input I have at this stage can serve to make life much easier come the shoot!

My plan would be to use my normal lighting gear (Gekko KelvinTile LED panels, Arri 650 and 150 Fresnels) and practicals to light the interior, have the windows have venetian blinds over them, and burn them out with one honking big light per window. I plan to have that shining through a big white sheet when direct sunlight is slanting in, and pointed at a big reflector for when the sun is indirect from that side of the building. I'll use my hazer to give this light a bit of presence on set (offices in the 1930s would probably have had lots of cigarette smoke anyway). I'll raise and lower the lights to change the angle and mildly gel to simulate changing time of day.

Am I making a huge rookie mistake?

What should I use as the honking big lights? I'm concerned that as this is a barn, not a regular soundstage, we may be very limited to the electrical power we can suck up (this is top of my list to figure out when we recce- I've requested the production hire a sparky to come along). I'm worried because when similar setups are described in American Cinematographer, they talk about 6K and 12K HMIs - that's not going to happen for this film.

I'll be shooting it on my Scarlet and if I possibly can I'd like to shoot at f/4, ISO 400 ish but I can already guess we may be forced to f/2.8 and ISO 800. Obviously I'll test, but advice from old hands would be hugely welcome!

Plan A: Power no object. Cheap cheap tungsten, with mild CT gel. I may not be able to lose the intensity of a full CT blue, but quarter or half should give the impression that the daylight is bluer. Options are anything from multiple 500 W worklights through stage 1K PAR cans through to 2K blondes (maybe one per window?). I need to know how many windows and how much power, ASAP. I'm very concerned that this will be pathetically dim, having run a test with my 650 Arris.

Plan B: Hire HMI. This would probably be my preferred option. How does one 575 W Arri per window sound? I can hopefully squeeze several of these in under the power budget, but might have an issue with the cost budget. 1.2K is possible if there's just one or two windows.

Plan C: LED. This may be the only solution if power is the major limit. Worst case scenario is a single 240 V 13 Amp circuit, in which case I'll be strongly recommending that the sets be built with just one small window and using all my cheap LED panels to make some dim and feeble attempt at daylight, whilst relying on the nice high CRI Gekkos to do the lighting of the talent on set.

Any advice gratefully received!

I don't think the production will stand or fall on how much like daylight my windows are, but since they are going to be in most scenes I'd like to do the best job I can.

Cheers, Hywel

Oliver Hadlow Martin · April 6, 2013

Can you rig lights from the ceiling? Can you get a generator up there so you can use biggers light, how big is this barn? Pictures?

David Mullen ASC · April 6, 2013

Generally to recreate daylight on a set you need a combination of hard and soft light coming through the window -- the soft represents skylight and the hard represents the sun, and you can obviously just have soft light with no hard sun coming through, but often you want some soft light coming through even when the hard sun is coming through. You also need lights to light any backing outside the window, even if it is just white. You would normally minimize use of practicals as a source inside because seeing them turned off is one of the visual clues that this scene takes place in daytime.

It would be very hard to do all of this if you only have two or three 20A household circuits in the barn, unless it's just one window. Yes, you can start out with the most power efficient lights -- LED's & Kinos for the soft, HMI's for the hard -- but even then you may be running out of power quickly. For a small window, a 575w HMI would work fine for a hard sunlight effect, but if the window is larger, it will have to be backed-up to fill it and it may not read bright enough for full sunlight unless everything else is knocked down in relation and you use a fast lens or a higher ASA. Of course, you could justify a "spotty" patch of sun, pretending it's coming through a gap created by two buildings, etc., that doesn't fill the window frame, and then compensate with the soft skylight effect coming through...

I had space limitations on a set built inside a warehouse with 13' ceilings -- to create the soft skylight we put bounce cards at the top of the ceiling at an angle and tungsten PARCAN's on the ground pointed up at them. There were also some lights along the air conditioning duct pointed back at the translight backing. For hard sunlight, I had to use lights on stands (generally a 5K PAR or 1.2K PARCAN firestarter), but sometimes I could rig them to the ceiling:

Noel Sterrett · April 6, 2013

I'm guessing outside the rehersal studio for "Smash"? If so, it played quite well.

Cheers.

Hywel Phillips · April 6, 2013

Thank you, David. A perfectly illuminating reply (if you'll forgive the pun) and that picture is worth a thousand words.

Much obliged.

Hywel Phillips.

David Mullen ASC · April 7, 2013

Another set:

In this case, instead of bounces, the soft skylight is coming for Image 80 Kinos. Since the windows are frosted, we didn't need a backing outside of them but we did put some light bulbs on the backside of the set to illuminate the stage wall seen (barely) through the glass. In this photo, the window was off-camera so I covered the whole window with Grid Cloth and put a 9-light through it for a soft side-key but in most cases, the Kinos were enough light to create a soft window light in the room and get me up to an f/4, it's just that since the Kinos are mounted above the windows, the angle of light is downwards and doesn't reach across the whole room as well as the lights on stands could. On some sets, I've put the Image 80 rows on a motorized bar so that I could raise or lower them depending on how far I wanted them to dig into the room. The Kinos have the advantage of being able to be rigged with a mix of daylight and tungsten tubes for a cooler effect at a 3200K base setting on the camera. The downside is that I can't dim them fully up or down on the dimmer board, just turn off select tubes. The other advantage to the Kinos is that they pull less power and generate less heat on the set.

Vedran Rapo · April 13, 2013

Great post David!

Brian McCann · April 19, 2013

Hi

I am definitely not a seasoned pro but I recently did day for night in a power limited location and was pretty successful I think.

The room I was in had two normal sized windows. From the top of the window frame I hung two daylight fluorescent bulbs a piece. They were cheap daylight photo bulbs from china. They draw 45w a piece and are advertised as having a 250w tungsten equivalent output. I don't know if that's really true but they are bright. They just hung from a cord like the one you put in a china ball. Behind them on the window itself I put white seamless to reflect and even out the source. I put a big piece of light diffusion in front of both bulbs and had sheer curtains in front of that. This whole technique only works if you are ok with using shear curtains which means not really seeing out the window. For hard light coming through the window I had a 650 fresnel in the room with full ctb. Its output balanced nicely with what the fluorescent bulbs were doing.

If I remember right we shot mostly at f4 iso 800. I was able to get the most from the lights since the camera was basically looking straight at them. I wanted the windows a little blown out but you could probably not blow them and it would still work. I had the idea and wasn't confident it would work but I was pretty pleased with the results. I'm not saying do this exactly but I think you'd be surprised how little you really need to do day for night. You save a lot of power by having the camera look right at the light rather than a bounce.