I got to wondering about this when I was watching The Terminator (1984) recently. This is one of my all-time favorite movies, and I think has some of the most beautiful and iconic night scenes in any film, accentuated by the mercury vapor streetlights on the streets of Los Angeles at the time. However, I noticed recently in the opening scene of the movie where Arnold Schwarzenegger stares over the edge of Griffith's Observatory at the city below, you see what appear to be a combination of MV and HPS streetlights. I remember reading that LA began replacing MV with HPS in the 1970s, so this makes sense. Yet all of the streets that the film is shot in are clearly almost entirely lit by MV. I seem to remember other 80s and 90s movies that have mostly MV lights, and I remember that whitish-blue lighting in a lot of newer movies, too. This got me wondering, did filmmakers prefer MV over other HID lights, particularly in the early days of HPS? If so, did the better CRI of frosted MV over HPS have something to do with it? I haven't read anywhere that they intentionally shot the film on streets lit by MV, but I wouldn't be surprised; James Cameron is known to make attention-to-detail decisions like that.

The scene I was referring to is here; starts at 1:08: https://youtu.be/UjpBs2BfNbw?si=16da520OiTKyjyxv

In many of the John Wick scenes, mostly outdoor fighting scenes, they appear to be lit by MV, but it is probably just a filter. The higher CRI probably helps, and the color probably gives things a more intense, evil, or scary look.

Interesting. I've also noticed that a lot of the lighting filmmakers use seems to produce a color similar to MV.

I've also noticed this, especially for scenes looking down long roads.

Nothing you see in movies actually is the color the eye would see when you were there, right in the action. Everything gets color corrected, regardless of whether it's digital or analog. But especially these days, it is highly likely that the yellow HPS light would selectively be color corrected to something more fitting the movie's atmosphere, since with modern editing tech that's just much easier and more perfected.

Shooting movies with HPS light is and making them look good is very hard, so they might call for just selecting the exact HPS color and turning it a desaturated green to fit an urban dystopia kind of look. The greenish MV look fits urban scenes and 'Neon Underground' much better than the golden yellow of HPS.

It also depends on where they were shot. In the USA, it seems that MV street lighting was the standard for a long time. However, i grew up with LPS and HPS with fluorescents mixed in in residential streets. Amsterdam is still about 50% HPS so any night movie shot in the last 35 years should in theory be either neutral (when it's a street lit with fluorescents, usually 3000k) or golden yellow (HPS). I have never seen mercury vapor public street lighting, only on parking lots etc.

But i'm sure that if you're gonna look for it, you'll find scenes shot under HPS light that actually look the part. For instance - this is a random shot from Drive (2011).

Update - I never thought this would ever happen, but https://youtu.be/1Vjd6NmA9Hs?si=Q8FeE5m7VTbl1bv0 this video (skip to ~2:30) that dropped yesterday pretty much confirms what I suspected. James Cameron says that they went around LA with a light meter looking for streets with bright enough lighting to shoot night scenes on, and explicitly says they settled on streets lit by mercury vapor lamps.

The outstanding performance of HPS for outdoor lighting does not come down only to Lumens, but to our eyes and brain ability to complete the full image from an otherwise very unbalanced input (a scene lit by non uniform, near monochrome, orange light)

(Incidentally, those is the very same reason why LED outdoor lighting achieves the exact opposite for our eyes, but might actually perform well for a video camera)



Dynamic range :

Our eyes have very wide dynamic range. Every time you look from an outdoors location under bright sunlight (100000 lux and higher) into a dimly lit lobby of a building through an entrance door (can be as low as 100 lux), you are seeing at the same time two areas with 1000x difference in the average light levels, and able to perceive what is it that you see in both of them

Under HPS (or really pretty much any) outdoor lighting, there are areas under the light which are brightly lit, and areas away from the light that get dim lighting. HPS does not ruin night vision, therefore it allows us to make use of huge dynamic range

Video cameras of the 80s have awful dynamic range. Even today's cameras are a far cry from the capabilities of our eyes. It is possible that filming under HPS would capture a scene which is well lit or even clipping directly under the light, but have an abrupt cutoff area beyond which it is unable to capture

Under Mercury light, the light in the area to be filmed have possibly higher uniformity and lower intensity, allowing the camera to see a wider area correctly within a single brightness setting



Color rendering :

The tiny amount of blue and green in HPS spectrum is all it takes to provide us with full color vision

Our brain understands that the light itself is of orange color, and extrapolates from the little blue/green the eyes see to understand what each surface in the scene would look like under natural light. Then, it is matched to things we are familiar with as reference

A video camera does not do any of this. The image is quantified into 3 color channels of an image sensor (which sensitivity spectrum is completely different from any cells in the eye), each of them is stored on and read from media (with or without correctly matched gain), and finally displayed on 3 color channels of a screen (with light spectrum that have nothing in common with the original spectrum at the scene, or even with the camera sensor)

Now, instead of the 589nm peak of Sodium light + little more info in other areas of the spectrum, we are presented with a scene with "the same colors" but is actually recreated either with wide emission spectra of Green and Red phosphors (CRT), or is filtered down from the emission of Fluorescent or LED (LCD), or UHP Mercury lamp (in the cinema), made from data already corrupted by the camera

Our brain won't know what to make of it, and either won't, or won't successfully, do what it can with the real life scene

And provided the awful dynamic range, the blue and green data will probably be nearly fully lost already at the camera anyway

With Mercury light which is white to begin with, there is much less to go wrong here