[The Great White Hope (Pre Project Thread)]

Generally speaking, 6500k White is common because it's the best compromise between brightness as color quality. The "bluer" you go, the higher the brightness (based on equal power). The "warmer" you go, the lower the light output.

From a usage standpoint, 6500k is on the blue side for most, but not unlike moonlight, which most people's eyes are used to at night - and visual acuity is actually better with a higher k temperature (this is why visibility under metal halide lamps is sharper than under sodium lamps, for example). It's a better color for backlighting blue, purple, etc.

Our 5500 (nominal, usually 5300-5400) is a much nicer "actual white" which I would consider "sign white", as it is closer to the color of a Daylight Fluorescent lamp than 6500k neon, even though a Daylight lamp is actually supposed to be 6300k. My experience is that most neon and/or LEDs that sell as a 6500k are actually cooler, some pushing 7000k and beyond. A white in the 5300-5500 range is still going to give you a nice punchy white, but also be able to backlight pretty much any color in the spectrum, especially brighter colors. It goes right from red to yellow to green to blue with no trouble because of the higher CRI.

Once you get into even warmer colors (the range between 4400 and 5200 is seldom used), your output drops further still, and is useless at illuminating blue, purple, etc. You get nice neutral white (3500 - 4100, like most halogen lamps), what I call designer white (3000 - 3400) and warm white (2600 - 2900) that replicate incandescent light... these are seldom used for illuminating channel letters, but for backlighting a large format images, posters, etc - anything between 3500 and 5500 will do a much better job than 6500k light sources. We're working on a large airport project that is using a 12 color printing process for the digital prints, and 5300k was deemed to be the perfect white source for backlighting.

I agree with the challenges of the darker colors such as blue, green, purple, & burgundy. They're even a challenge with 6500K. But, it offers the best option because of the "blue" in the light.

Plus, I've seen how a warmer white (3500K) seems to work better with the day/night acrylic or film as compared to using 6500K. It doesn't look great but it looks brighter. But, getting the end user to accept it is the challenge and that means samples need to be provided to aid in the decision maing process.

I'm agreeing with you on the use of 5500K for channel letters as I find it more appealing. But, when dealing with the end user it's based on what they want and like which may go against what you are proposing. With that everybody has a different concept which makes it difficult to establish any kind of a true standard. For me just having some guidelines to work with helps in the decison making process and has helped in working with the end user.

[The Great White Hope (Pre Project Thread)]

I have one odd thing to throw at you - our AXLE3WG65-3 module will probably only need one stroke on an 8" letter.

I hate it when "will probably only need" ----------is used.

On choices of white --- I personally think that 6500 white needs to be used as a "standard" and then go on from there. Why? Because that truly is the standard by which even egl 71 is compared. Depending on whether you're looking at "color", "brightness", or "enough" as in even light as the defining terms. Since perceived color is totally up to the client, and brightness is not a measureable term, "enough light" comes into play quite often. What you'll find in this sample test---is that "colors" are all over the place. Visual "brightness" is all over the place. And "enough" light is hard to determine. 6500 white ------has a range of Kelvin color. Led's are all over the place. If you turn on ANY letter, lit up by whatever your favorite choice is ---------- it usually looks pretty good. When you light up a second, and can compare----now the choices come in. Is it "whiter"? Meaning what----a bluer white, or a milky white. Your preference for the best is the determining factor. Leaving "brightness" out since it can't be measured, and looking instead at lux or lumens-----is there really enough difference to really care about? So, then, is it bright enough? IF instead, you set up a letter at one end of a dark room, and another at the other end of the room -------------- and then had to judge back and forth, rather than a side by side comparison ---------- the answers wouldn't be quite so evident.

To compound all this --------in your samples. MOST led mfgs have different leds for different faces, and different choices for how much your cus;tomer wants to spend. Should we use the cheap axioms, or the more costly. The cheaper Sloan, or the more expensive Sloan, the cheaper Gelcore, or the more expensive ----------- and then, ask yourself why that particular one.

One of the absolute best demos had virtually ALL the led's in samples--------and you could truly pick and choose which ones you wanted to light up and compare ---------- made some look pretty darn sick which comparing side by side.

gn

I find you comments interesting. Based on this it seems that the standard hasn't been established although most seem to default to 6500K. I'm just starting to see the advantages of the different color temps depending on the face color and materials.

[The Great White Hope (Pre Project Thread)]

Correct color being 6500 K??? I didn't say that-------What I said was that it would probably be more considered as the "standard". Personally, I always liked the 4500. That used to be standard millions of years ago. And then 6500K came along. Manny asked, and I'm not sure if he was being facetious or not, as to whether we "buy" neon in a range of K. If he was referring to buying 4500, or 6500, or 7100, then obviously yes. If he was referring to the range of K that a mfg decides that 6500 is in --------no, I don't, but you can't tell me that Voltarc 6500 matches EGL 6500 either.

When I referred to "enough" ---- it wasn't that Eric wouldn't have enough choices --- it's just that enough light becomes more into the equation in what a particular customer wants based on price - and often that trumps brightness, and color of white.

And Manny, I personally feel that an LED mfg should be involved in deciding which of their many products should/should not light up a particular letter, much in the same way that Eric should rely on his tube bender to help in the decision process, regardless of whether the decision is millimeter of glass, or the correct color to use, or the proper layout of the tubes.

Personally, cheapest is not always the best way to decide a product - any product, or any service. And when you speak of Monigle or whomever spec'ing out products - obvious they do. But, we also get our fair share of clients that come in and look at our board of letters, with plex, with neon, with different LED's ---------- and they get to pick based on what it is that THEY are looking for with guidance, rather than someone deciding what they need based on price, or someones decision on which is the best white, or someones decision that brightest is the cure-all for whatever ails. That's why your product is on the board like everyone else's.

Quite simply, depending on the size of the sign shop, the customer involved, etc ---- choices for the client are often times dictated by the company that makes the sign, and quite often are based on the bottom line concerns of the sign company ---thus the price of the components alone---and that is not often the best choice for decisions.

gn