Times when staff didn't follow best practices or local policies for new infra

[danbrotherston]

LEDs themselves of course emit a specific wavelength (blue) but in modern white LED lamps, the blue light is passed through a phosphor to adjust the spectrum to white, and the resulting light is very broad spectrum, far better than low pressure sodium lights (which we didn't use, but are common in some places) and certainly not worse than high pressure sodium lights (which we did use before).  They are a higher colour temperature which does affect one's perception of brightness.

Given what we already knew when the decision was made by Kitchener to start using these LED lamps about how bluer light screws with your circadian rhythms and increases the risk of many diseases, I'd say that they are definitely worse than the old orangey sodium lights in that regard.

 Leaving aside whether the data is clear on that or not for the moment.

I think you are confusing colour temperature with spectrum broadness. Spectrum refers to how many different wavelenths of light are present in a light source. You can make a light source appear white with only 3 different (I think) wavelengths of light, where as traditional sources such as sunlight or incandescent bulbs will have light from all wavelengths in the visible spectrum. Having light in only a few wavelengths will appear white (or any colour you choose to make) to the eye, but it will not look normal when objects are lit.

Fortunately, white LEDs as we have used emit a broad spectrum of light closer to an incandescent bulb, meaning objects will look normal when lit by these bulbs. This is opposed to some light sources which emit only a few wavelengths and drastically distort the colour of objects lit by those sources: https://en.wikipedia.org/wiki/Sodium-vap..._lamps.jpg

In terms of colour temperature, yeah, LEDs were chosen with a higher colour temperature (you're right this was a choice). Whether you consider that a good, bad, or neutral thing well, I don't personally believe the data is all that conclusive--certainly there are indications that it can cause problems, but there are also some benefits (you need less light to achieve the same perceived brightness). But mostly I believe focusing lumiares onto the areas that need lighting and thereby limiting spread of light and otherwise limiting unnecessary lighting is a more important than the colour temperature, but that's merely my opinion on the matter.