[BorgHunter]

It depends strongly on implementation. LEDs can produce white light at any color temperature and CRIs ranging from terrible to great. Quality LEDs are quite nice indeed (when they're not turning purple).

Most LED streetlights replaced sodium vapor lights, though, which produce the sickliest, most horrible orange color known to humanity. Just about any LED is an improvement over those.

[goku12]

Strange! I was going to say the exact opposite. I find the near-white light from LEDs very harsh and tiring to my eyes. I often end up rubbing my eyes under them. The sodium orange feels cooler and easier. The strain on my eyes is similar to daylight, but without the alertness it induces. (White LEDs actually feel worse than daylight, for some reason)

There were articles a few years back stating that the blue emissions from these LEDs were rather energetic and damaging to the retina. Conversely, some articles used to claim that red light actually improves the health of the retina. I don't know if those results were corroborated or debunked afterwards.

I know that personal beliefs and biases affect our perceptions. But such diametrically opposite experiences are surprising. I'm curious to know what everyone else experiences and any insights on this.

[hedora]

Sodium lights aren’t even orange in the normal sense of the word. They only emit one wavelength.

[addaon]

> Sodium lights aren’t even orange in the normal sense of the word. They only emit one wavelength.

It's hard to think of a more normal sense of the word "orange" than "emitting and/or reflecting predominantly wavelengths between 590 and 620 nm." I guess you could argue that sodium is close enough to that lower edge to be yellow?

[adrian_b]

There are 2 kinds of sodium lamps.

Low-pressure sodium lamps emit a single wavelength and they are the only kind of lamp that does not use LEDs, but which can match or exceed the energy efficiency of LED lamps. However, with low-pressure sodium lamps you cannot perceive any color.

There are also high-pressure sodium lamps. They emit a broad-spectrum light, even if with an excess of orange-yellow light. You can perceive the colors of things with such lamps, even if not very well. However the high-pressure sodium lamps have a much lower energy efficiency than LED lamps.

In Europe I have encountered mostly, or perhaps only, high-pressure LED lamps used for public lighting. I have used at home some low-pressure sodium lamps for certain purposes, but I am not sure if I have ever seen one like that used in a public space, here in Europe.

Low-pressure sodium lamps typically use transparent glass bulbs, like incandescent lamps or any other kind of low-pressure gas-discharge lamps, e.g. neon lamps.

High-pressure sodium lamps use special bulbs made of translucent alumina ceramic, because glass would not survive in those conditions.

[wiredfool]

I thought it was two - the sodium double emission line.

[adrian_b]

The lines are so close that their hues cannot be distinguished by a human eye.

[looofooo0]

What is the normal sense of the word? I only know the CIE standard observer to define colour and with this it is clearly in the equivalence class of orange.

[lukas099]

I think they mean they don't emit a "natural" orange (like an orange flower) that is really some kind of sum of many wavelengths. I could be wrong though.

[adrian_b]

A pure orange contains only light with a single wavelength.

A mixture of light with different wavelengths that is perceived as orange cannot be distinguished from a mixture of some pure orange with a certain amount of white light.

So any orange, of a flower or of anything else, has the hue of a single wavelength, but it may be more or less saturated, appearing like light with a single wavelength mixed with some white light.

Low-pressure sodium lamps emit a pure color that belongs to the yellow-orange range, so you could describe it as a yellowish orange.

High-pressure sodium lamps have a desaturated orange color, i.e. light that looks like a mixture of orange and white lights.

The orange of any kind of sodium lamp is much more yellowish than the reddish orange of neon lamps with cathodic light, like those used in neon indicators.

Most sodium lamps contain some neon for starting, so when they are switched on they may emit a reddish orange light for a short time, then change to a yellowish orange light, when the sodium vapor takes over from neon.

[xattt]

If orange was tolerated before, I am curious why orange LEDs aren’t being looked at again for resilience.

[looofooo0]

Well we cannot manufacture orange LEDs with good efficiency.

[Lammy]

> Quality LEDs are quite nice indeed

This is true but irrelevant when cost reduction is the motivating factor for switching to LED lighting, because that motivation will extend to the upfront purchase cost of the lamps and they will buy whatever is cheapest.

[BorgHunter]

It depends, obviously, but when installed by governments, "cost reduction" almost always takes into account labor to replace faulty lamps, which is especially relevant when there are thousands of the things out there. So governments (for the most part--there are exceptions) avoid the cheapest ones, correctly identifying them as a false economy. The cheap ones are most likely to be found in private parking lots, because parking lot owners are generally only responsible for a handful of lamps and it's a pretty minor part of their business, so they're not going to put much thought into it.

[kjkjadksj]

The benefit of sodium vapor is it emits a narrow band wavelength. So then if you want to engage in astrophotography you can use a narrow band filter and eliminate quite a lot of local light pollution.