advanced

Street Lighting

>>>Super White Flame (off the top of my head I think it is LEE gel #232) in >>recreating the look of street lighting.

Hi Joel

Is this Super White Flame plus Tungsten light on Tungsten film to recreate mercury vapours or sodium’s?

Thanks

Byron Shah
DP Los Angeles

Byron Shah wrote :

>>>is this Super White Flame plus Tungsten light on Tungsten film to >>recreate mercury vapours or sodium’s?

White flame green plus naked tungsten won't get you to a sodium vapour yellow/orange. At least, not on tungsten balanced stock.

It may be a good equivalent for mercury vapour though.

A combination I like for sodium effect is;

LEE Filters:

245 HALF PLUS GREEN
442 HALF C.T. STRAW
744 DIRTY WHITElike

Tom Townend,
Cinematographer/London

Byron,

I've used Super White Flame on HMI fittings to recreate sodium lighting on daylight balanced film or when shooting HD balanced for daylight.

Tom,

White flame green is a different gel altogether.

Joel Devlin

DP, UK

>>>I've used Super White Flame on HMI fittings to recreate sodium lighting >>on daylight balanced film or when shooting HD balanced for daylight.

What would be considered a good example (major motion picture) of a scene done with available sodium vapour light?

A lot of attempts to create this look appear quite unnatural to me.

It's a struggle in post to finesse a scene shot in available sodium vapour (street) lighting. The discontinuous spectra of this type of light can cause some strange problems related to acquisition-response AND colour content in staging.
____________________

From WIKI :

>>"...These lamps produce a virtually monochromatic light in the 590 nm wavelength. As a result, objects have no colour rendering under a LPS light and are seen only by their reflection of the 590 nm light (orange)..."<<
____________________

I find dealing with the green (there is a big green spike) is usually problematic.

The following sums up the problem nicely...
____________________

From WIKI :

>>>"...For a source like a low-pressure sodium vapour lamp, which is monochromatic, the CRI is nearly zero..."<<

____________________

A CRI of zero should set off some alarm bells for most DP's!! Sometimes it can look great. Other times, there can be a disappointing skew to the colour and it's pretty easy to underexpose.

Is there any truth to the rumour that urban planners are going back to specifying mercury-vapour lamps for street illumination? They certainly seem to come across better photographically.

David Perrault, CSC

David Perrault wrote:

>>The following sums up the problem nicely...

>>From WIKI :

>>"...For a source like a low-pressure sodium vapour lamp, >>which is monochromatic, the CRI is nearly zero..."

It's important to distinguish between High Pressure Sodium and Low Pressure Sodium.

Most Sodium vapour street lights in the US are HPS.

LPS (Low Pressure Sodium) lamps do indeed have a near Zero CRI. They are popular because they are the most efficient in terms of lumen/watt and burn time. HPS (High Pressure Sodium) lamps, while less efficient, can have a CRI of 22-75 depending upon the exact type of bulb.

There is also a type of "White" HPS that approaches a 2800-3000 degree tungsten lamps in CRI, but these are generally not used in street lights since different manufacturers lamps are not interchangeable.

Even newer designs of Mercury Vapour lamps generally have a lower CRI (15-55) than HPS lamps.

>>Is there any truth to the rumour that urban planners are going back to >>specifying mercury-vapour lamps for street illumination?

You may be thinking of Metal Halide lamps which can look a little violet/blue like MV lamps, but have a much nicer light MH lamps have a CRI 65-80, and the more expensive ceramic MH can have a CRI that reaches the low 90s.

>>They certainly seem to come across better photographically.

The MH lights are terrific compared to the rest, but are less efficient. They're generally considered too expensive for street lights, but they are extensively used for architectural lighting. I think some areas of NYC that have their own management districts -- like Times Square -- have installed MH street lights.

Brian Heller
IA 600 DP

How can you tell the difference between HPS and LPSodium?

Best

Byron Shah
DP Los Angeles

Byron Shah wrote :

>>How can you tell the difference between HPS and LPSodium?

High pressure sodium is generally brighter than LPS, and has a Pinkish/Orange colour. Low Pressure Sodium is much more yellow/orange.

Stuart Brereton
DP, UK

Byron Shah wrote :

>>How can you tell the difference between HPS and LPSodium?

1/. The easiest way is by comparison with known sources. You can then train your eye to spot the difference. Just like spotting the differences between cool white and warm white fluorescents, it will soon become obvious.

2/. Under LPS lighting, every object with colour will be seen as a shade of brown or black . On the other hand, there will be a marked improvement in colour rendering under HPS lighting. Try viewing a colour chart under different light sources.

3/. If it's a mall or shopping center parking lot, ask the maintenance people what kind of lamps they use. For city streets, the public works department electricians can tell you.

4/. Spectroscope. There are lots of websites detailing how to make your own. I think Edmund Scientific sells high quality versions, but a simple one will do.

5/. Colour meter, but for comparison purposes only.

Brian Heller
IA 600 DP

>>It's important to distinguish between High Pressure Sodium and Low >>Pressure Sodium.

Good point.

The most typical environment for LPS fixtures are warehouses that feature large volume and area with few people - typically big box or bottle storage facilities, and LPS lighting can be very misleading when it comes to pulling out a light meter.

It's important to recognize when available light is continuous or discontinuous spectra. Similarly, colour temperature and CRI are not related.

LPS, HPS, MV and MH lighting all exhibit similar characteristics with regards to continuity of spectral output., and they all have, for the most part, less than ideal CRI. Lot's of these lamps get into cycling when they get old. This can be really weird when there are a bunch of different fixtures glowing on and off at irregular intervals.

David Perrault, CSC

I was just curious (and this may have been asked in the past) if anyone has checked out the CT on those freeway work lights that you see being used at night? They seem, to my still-in-training eye, to be close to the HMI/5600 end of the spectrum and if I read him right Lubezski used some of these during the 'Children of Men' shoot.

How would these register on film?

Chris Fernando
1AC
Los Angeles, CA

Chris Fernando wrote :

>>I was just curious (and this may have been asked in the past) if anyone >>has checked out the CT on those freeway work lights that you see >>being used at night?

It depends on the units in use. Some of the newer "light towers", which is what they're usually called in the construction trade, use 1000 watt Metal Halide lamps which have a respectable CRI of 65. Ceramic Metal Halides can have CRI of 92 0r more and are available with equivalent colour temps of 3200 and 5000. Remember, these are still discharge lamps and do not have continuous colour spectra.

However, there are some light towers set up to use industrial quartz lamps, which are just a little warmer than 3200. The real problem with any of these light towers is noise, since the attached generators are not silenced. However, if you can't afford a Musco, they are might handy indeed.

Brian Heller
IA 600 DP

Chris Fernando wrote :

>>I was just curious (and this may have been asked in the past) if anyone >>has checked out the CT on those freeway work lights that you see >>being used at night?

Hi Chris,

I've used these lights many times on film shoots. "CSI" used to use them a lot, too, when I was working for them. We called them "Wacker" lights, since that was a brand name, and had even made up pigtails that could adapt them to plug in to our camlock power distro. This overcame the generator noise issue Brian mentioned. If I remember correctly, it's commonly a 220V system.

Typically, they're metal halide lamps, and you can use half-green gels on your HMI's to match the colour pretty closely. They're not flicker-free, so watch your frame rates\shutter angles, and I've beaten up my hands pretty badly on some of the older ones, trying to loosen the lights so they could be focused. They tend to sit out in the weather a lot, and the bolts can get rusty and frozen.

Also, I saw "Inside Man" last year, and it seems that they modified some of these units to use the Arri X lights, which looked really cool with the squared heads and daylight colour.

Best,

Graham Futerfas
Los Angeles based DP
www.GFuterfas.com

Chris Fernando wrote :

>>I was just curious (and this may have been asked in the past) if anyone >>has checked out the CT on those freeway work lights that you see >>being used at night?

I've just done a little checking with Power Electrics here in the UK.

These towers use 4 Phillips HPI-T 1000w Metal Halide lamps. CCT 0f 4300k and CRI 64. The generator units are pretty quiet these days, and come with a 32amp Cee-form power output as well as powering the lamps. They rent for about £110.00 a day over here. As Brian pointed out, there is probably a flicker issue, but as long as you're careful, it seems like a pretty good 'budget' alternative to movie lights.

Stuart Brereton
DP, UK

>>What would be considered a good example (major motion picture) of a >>scene done with available sodium vapour light?

I thought Fargo did it quite well with full CTO and half CTS on tungsten lamps.

Art Adams
Director of Photography
Film | Hidef | Video
San Jose, CA, USA
www.artadams.net

>>I thought Fargo did it quite well with full CTO and half CTS on tungsten >>lamps.

I agree.

But I was hoping for references that are/were completely available lit.

David Perrault, CSC

I did 2 films in the past few years that had street scenes at night that were completely lit by existing streetlights due to the expanse in the shots and because I also like the "natural" look that it has. I try to avoid BFL's on condors or Musco type fixtures whenever I can. That feels artificial to me. There are a couple of shots in "Stay" (2004) and a few in "Stranger Than Fiction" (2006). In the latter, the scene where Harold gets off the bus and confronts Kay in front of her office building is an example which comes to mind.

Roberto Schaefer, asc

Roberto Schaefer wrote:

>>I try to avoid BFL's on condors or Musco type fixtures whenever I can

Hi Roberto,

I'm prepping a movie with tons of night ext work none of which can look like night exteriors, therefore no BeeBees, no Muscos, etc.

In the past I've gotten the art dept to rent mercury vapour street lights so we can position in frame; however they don't work so well as a key light--too dim, awkward to mount, etc. When you do need to augment available street lights, how do you do that? Do you use a 'whiter' light on skin tones? What gel packs do you find work to mimic Sodiums and Mercury’s?

Best

Byron Shah
DP Los Angeles

Hello Byron:

A couple of years ago, Lightning Strikes :
http://www.lightningstrikes.com/ had a dog and pony show here in Houston.

At that time, they brought with them some vapour lighting units (sorry, can't recall if they were sodium or mercury) that they had adapted for movie work.

You might want to give them a call to see if they still have the units.

Best wishes.

Sincerely,
John Sheeren
DP/OP/AC
610 East 9th Street
Houston, Texas 77007