Want amber led that will mimic the color of HPS lamp?

[EricB]

There's a kind of "soft white" LED that appears to be lower in Kelvins than the 2700's that are out now, and when seeing a bunch of them together, they resemble HPS. I have never been able to find any info on them (like how many K's), nor have I seen them sold in any form yet, but I've seen rope lights of them as store window displays, and this store is covered with them at Christmas time: http://maps.google.com/?ll=40.76072...=13,-239.69801252335873,,0,-5.729577951308144
(Next to the 2700 and higher LED's on nearby stores, they really do look "copper" or similar to HPS).
Perhaps they are starting to use them as incandescent replacements for cars? (Where the 6000K's alredy used for the white "Reverse" lights would distort the colors of the red or amber lights).

 

[och]

I though HPS was a yellowish color, LPS was orange?

 

[Canuke]

I've find that mixing one cool white (about 6000K) and one amber led behind an opaque layer will be quite similar to HPS light. I find this trying to get warm white (incandescent looking) but the result was not to my liking, -it looked too much, pink HPS light for me

This. A few years ago I went camping on Thornhill Broome beach in California, and the park ranger shack had an outside area light that looked like HPS, but on close examination I noticed it was full of cool white and amber LED's.

The *blue* spike is what gives HPS its characteristic color, in combination with the yellow band it shares with LPS. The varying shades of HPS are a function of variations in that blue band. If you get a CIE color diagram and draw a straight line between 590nm and about 450 nm or so (I don't know exactly where that blue is), the line should cross all those shades of orange and pink that HPS can take on.

 

[Canuke]

EricB: I Was going to say that I've never seen those, but upon reflection I think I have. I was in a restaurant (Fleming's in Las Vegas, I think) and they had those little battery-operated LED votive candles for decor. But these were not emitting that usual amber, the light actually looked much more like the warm orange of an actual flame. I tried to find out where they got them, but nobody knew.

I don't know whether these emitters are rare or expensive, but they sure would be a lot more appealing in rope lights and other decorative applications than monochromatic amber (or its Halloween orange counterpart) could ever be.

 

[Canuke]

EDIT: I think I found the source, they were probably 5mm amber leds from Nichia, it is the only company that makes 5mm PC amber, evident from higher V_f and wider SPD curve in the datasheet of NSPA510BS. (But puzzlingly their x,y value is still very near the spectral boundary!)

Brookstone has (or had) their own keychain lights that used phosphor-based yellow and pink emitters. The yellow had a much more "lemony" quality to it that monochrome yellow does; I think that most yellows we see in the world are actually rather broad in their reflectance spectra, including from red through to green -- not-blue, in other words.

 

[EricB]

I though HPS was a yellowish color, LPS was orange?

I meant HPS (I call it "peach" color, as it's pale and pinkish, basically whitish orange; whitish from having the blue in it, as Canuke said). I don't know why I got that crossed with LPS, which is the monochrome amber (which is yellowish orange, but closer to yellow).

EricB: I Was going to say that I've never seen those, but upon reflection I think I have. I was in a restaurant (Fleming's in Las Vegas, I think) and they had those little battery-operated LED votive candles for decor. But these were not emitting that usual amber, the light actually looked much more like the warm orange of an actual flame. I tried to find out where they got them, but nobody knew.

I don't know whether these emitters are rare or expensive, but they sure would be a lot more appealing in rope lights and other decorative applications than monochromatic amber (or its Halloween orange counterpart) could ever be.

Candle LEDs usually are amber, but sometimes the illumination of the white plastic surrounding it makes the amber look paler like real flame. We have one of those bathroom scent candles, and when you're looking at the [diffused] light through the plastic, it does look like real flame color. When you look directly at the LED, it's amber, but also, perhaps because these things are usually used in the dark, I think that could also affect it. I noticed it tends to look paler. Might have to do with our eyes. (Like if you look at red for a long time, and then look at 590 amber (LED or LPS), it suddenly looks greenish "lemon" yellow instead of amber!)

Or maybe it could be what I was referring to. Trying to remember what other color I've ever seen those little tea lights in (I do know I've seen an RGB one). I don't think I've seen the copperish (HPS-like) lights anywhere but those decorations.

 

[anuragwap]

Deleted!

 

[Canuke]

ERicB: Our ability to distinguish saturation falls off at the dark limits of color vision; that amber is closest of the monochrome colors to candle light, so it still "works" fairly well when seen through the candle wax (where it mixes with ambient illumination reflecting off the wax). However, the LED candles I was discussing were definitely not amber, as I stared right at the "flame" and there was definitely blue light in it.

 

[EricB]

I don't know what that was, then. It could be the "copper" light I was talking about. I really can't tell looking it up, because when they say "amber" or "flame colored", you can't tell whether it's 590 monochrome, or the color you're looking for, or whatever else.

I guess eventually these will become more available (like I first saw really good 2700K LED's back in '05 in the LEDEffects showroom (when I was preparing to buy the DingDotz back then), and it's not really until the last three or so years that you can really see or buy 2700's everywhere. (First, you had the pale 3500 ones).

As for the Brookstone keychain, I saw the phosphor yellow (but not the pink) years ago, and yes, it's a nice lemons yellow pretty much like FFFF00 on a monitor. That's the only place I've ever seen it to date, and wonder why they never caught on anywhere. (You do see the pinks more, but never yellow).

What would be the closest color on the monochrome spectrum? Around 580? (570 green is close as it is. Maybe 575, then). I wonder why you don't see those wavelengths in LED.

 

[hank]

searching for: LED "580nm" "high power" turns up quite a few