The mercury question?

[AngryHorse]

So help me out here, I’ve been pondering this all week?, as we know, the humble MBF lamp had a CCT of 3850 K, close to the 4000 K of today’s LED lanterns on your average housing estate, but why do I look at today’s lanterns and automatically think ‘halide’ instead of mercury?

I tried to recreate that mercury look on my outside lighting using today’s LED retrofit lamps but with 4000 K defused lamps I still got a halide look!
Note: (if it wasn’t for today’s rip off energy prices, I’d have used ACTUAL 80 watt mercury lamps)!, anywho, back to the issue, to get that bygone mercury look I had to go with 6500 K lamps to get it to look like I remember the MBF days????

Have I actually forgotten what the 3850 K of mercury looked like, and why do I remember them as being more blue in colour? than the nearer 4000 of todays LED??
These photos below, (at 6500 daylight), look more how I remember our mercury street lighting to have been?

IMG_7756.jpeg

[Beta 5]

Possibly due to the lower CRI of a MBF lamp? The halides usually have a higher CRI in the 70-90 range which is more on the same lines as the LED's used in the lanterns, whereas the 50-60 CRI of an MBF probably makes it look "dirty", but gives it the unique appearance compared to the cleaner light of LED/MH.
I also think the light from a clear halide and an LED are quite sharp whereas a MBF is of course phosphor coated which softens it.

[AngryHorse]

Yeah that makes sense , I hadn’t considered the Ra figure?, I always remember mercury street lighting to have been blue, but their CCT just wasn’t!
It’s been an interesting experiment, and I’ll have to run a mercury lamp and a 4000 K LED side by side to see an actual difference?
I quite like daylight white outside at night though, (even though it breaks all the rules of us enthusiasts to use 6500 K outside)!

But in my mind my current set up is near to MBF as I remember as a kid!

[Beta 5]

It is an interesting topic! A comparison between an MBF and an LED would be quite good to see, it would also be interesting to see a 33-640 fluorescent alongside too, to see how the CRI differs between that and the MBF.

I know 6500K is usually a bad choice for outdoor lighting (the 4000K LED used in street lighting is too much imo), but in small amounts such as an 860/865 PL in a bulkhead can look quite nice with the way it shows up the green grass etc, especially if used with other warmer coloured lamps around.

[AngryHorse]

Man was this an infuriating experiment! , did the comparison couldn’t get the results as seen by eye!
So the iPhone lies! , in the photo the 4000 K LED on the left looks identical to the mercury on the right, but their not!, not by a long shot, the first thing that stands out with the 80 watt merc is its red content but I can not capture this at all, no matter what I do with the phone settings!
The LED on the other hand, yellow stands out, but its reflection in the GES lamp holder shows pink!

It’s really not!, my eyes see NO red content with 4000 K LED!, I got them both running next to me now, (in a different setting), and once again their two different colours, and again the phone won’t capture this!
I don’t know whether the mercury’s arc is playing with the white balance when you try and photograph them together, but with the naked eye, the 4000K LED looks like 3000 when it’s next to the merc!

[AngryHorse]

Ok, only by grossly changing the phone settings separately can I even get close to something similar to reality, but even here the yellow of the LED doesn’t come out!

IMG_8249.jpeg

[FrontSideBus]

Something I might have to have a go at.

[AngryHorse]

Cool!, if anyone can achieve this it’s you Mark! , but it’s impossible on an iPhone to capture the red content of yttrium vanadate on a fully run up lamp!
Is there some secret in photography to capture what our eyes actually see regarding artificial light? or could it be our eyesight is different for each person?

[FrontSideBus]

Cameras are more sensitive to different wavelengths. The trick is shooting RAW images and then tweaking it to match what you see.

[PeterG]

Personally I think its also about diffusion; you need some kind of opal cover surrounding the LED cluster so there is less of a sharp point of light source, as per MBF lamps with their opal glass envelope. I'd try that out once you are satisfied with the colour matching as its likely that sharp, sparkly point of light is why it looks like halide as halide has a sharp, sparkly point of light from the capsule in the clear glass lamp