I haven't heard the term "sodium mercury" lamps -- those discharge street lamps are either sodium vapor (orange) or mercury vapor (cyan).
Rosco makes two "sodium" gels for that look, one is called "urban vapor" and the other is called "industrial vapor". "Urban Vapor" is more like Apricot, sort of a deep yellow-orange, like how your eye thinks sodium looks. "Industrial Vapor" is supposed to actually convert tungsten to the color of sodium and is a horrible sort of yellow-brown-green color.
LEE Apricot was often used to create a high pressure sodium look before dedicated 'Sodium Look' gels existed. Some people just use CTO on tungsten, often with 1/4 plus green added. CTO and medium bastard amber also works. Roger Deakins apparently uses CTO and Straw Tint 013.
For Mercury Vapor, I like LEE Fluorescent 5700k on tungsten lamps.
So I was wondering what gels do you guys use when trying to replicate Sodium Mercury Lamps in terms of color ?
There is this Lee gel called Apricot that I have had my eyes on for a while.. does it do the trick ?
Also is there a difference between Sodium Mercury Lamps and Sodium vapour lamps in terms of color or are they both the same ?
Hi Vivek. I used the Lee Urban Filter package on my last short to replicate the sodium vapor look and found that Lee 652 worked the best for me. However, I recommend you test a number of different gels that are in the same family of orange until you find exactly what you want.
One point to remember is that Sodium Vapor lamps come in two different varieties, high pressure and low pressure. High pressure is a pink/orange color, low pressure more of a dirty yellow. Within these two types, individual lamps will vary wildly in terms of their look, so it's best to test in the actual location you will be shooting.
Streetlamps and most building fixtures will be HPS. LPS typically found in the lower wattages,
Or if you live near a working astronomy observatory. In San Diego and various places in the greater LA area, LPS was strongly 'preferred' one for lower power consumption but also because it is a narrower spectrum had less effect on light pollution for the telescopes on Mount Wilson and Mount Palomar. San Diego had a 30 mile radius from Palomar where LPS would be used over other sources.
I think Palomar is winding down, and so, I've noticed a growth in LED lights for general street lighting... I've also noticed lights have small 'blocking flanges or placement to less direct 'upward' or direct Line of Sight to Palomar.
This may also be the case for Tucson Arizona and the area of Mona Loa in Hawai`i where currently active astronomy facilities are located.
HPS lamps were introduced around 1970 and are one of the more popular street lighting options, the most efficient light source when compared to mercury vapor and metal halide lamps (on a ‘lumen/ watt’ scale). The disadvantage is that they produce narrow spectrum light mostly a sickly yellow in color. These lights have a very low color rendering Index and do not reproduce colors faithfully. These lights do not find favor with police departments as it is difficult to determine the color of clothes and vehicles of suspects from eye witness accounts in the event of a crime. Color-corrected sodium vapor lamps exist but are expensive. These "color corrected" HPS lamps have lower life and are less efficient.
There are two types of sodium vapor streetlights: high-pressure (HPS) and low-pressure (LPS). Of the two, HPS is the more-commonly used type. Low Pressure Sodium lights are even more efficient than HPS, but produce only a single wavelength of yellow light, resulting in a Color Rendering Index of zero, meaning colors cannot be differentiated. LPS lamp tubes are also significantly longer with a less intense light output than HPS tubes, so they are suited for low mounting height applications, such as under bridge decks and inside tunnels, where the limited light control is less of a liability and the glare of an intense HPS lamp could be objectionable.
I've noticed in Europe the use of these super-yellow sodium lamps for parking lots, etc. -- they seem less common here in the States. Would those be an example of Low Pressure Sodium?
It's likely that they are. In Britain, most streetlights are HPS, and have that distinctive pink/orange color, where parking lots and industrial areas will have LPS, which is a super saturated yellow/orange.
A lot of fixtures have likely been replaced by LEDs these days.
Yep, that's a full CTS (Colour Temperature Straw) on tungsten, with the camera's white balance at 4500k.
Very nice reproduction. That's exactly the hue I remember seeing outside of a pub called West End House when I went to Leeds in 2013. I remember taking a few pictures, so I'll see if I can find at least one.
For sodium vapor, I've actually found great success using real sodium vapor lamps. I love them because, much like other pressurized gas lights, they stupidly efficient and I can absolutely bake a room with lights on a single house power circuit (plus they're like $80/head - which makes production happy). Recently on both Black Mass and Spotlight, they employed a lot of sodium vapor lighting - but they just used 400w Sodium floods on condors instead of dealing with other lights. You get really gross looking skin tones and need to be careful about over amping and clipping the red/green channels, but thats generally 100% fine in situations that take place under where a sodium light would be located. I've used the both flavors of the Rosco vapor gel and whilst I appreciate them, they don't quite have the same quality (and I need a higher wattage light to really get a proper effect on camera because the transmission coefficient is so low). That being said, if power/budget isn't much of an issue, I would take the tungsten to have it as an option.
Anyone know if a light meter reading of a sodium vapor would be accurate or would it be inaccurate due to spikes in the spectrum (like with LEDs)? Paging Guy Holt!!