Need for warm vs. cool tint LEDs?

What is the need for warm vs. cool tint LEDs?

I understand that some of us prefer warm and others prefer cool tint LED lights. I've researched CPF about this point. As DM51 wrote, "It is very subjective.".

I'm not curious about anyone's preference. And, I'm certainly not trying to force my personal tint preference on anyone else. I prefer cool tinted LED lights, but am beginning to feel that I may be missing out on something.

In practice, I use: cool tint white, blue color, and UV LEDs for inspection quite often.

I wonder about specific uses for warm tinted LED lights. My research on CPF has uncovered three uses: critters, grilling food, and medical triage.

Are there any other practical uses for warm LEDs, or does the use simply come down to personal preference?

I think it's just personal preference. Ultimately a light is a light and the main purpose is to provide illumination.

For what it's worth when I started using warm and neutral white lights I never looked back.
For me it's more about color renditioning rather than any specific tint but if you can get a neutral tint with good color renditioning all the better.

I still own a few cool white lights and whenever I use them I just shake my head at how pasty and subdued it makes the colors look.

Warm emitters are a must for power outage lighting; the cozy and welcoming fireside hue is a pleasant morale boost where it's needed, whereas using a clinical, sterile cool emitter feels like sitting in your garage.

Cool emitters are better for desert use, where amber tints cause colors to sublimate and everything just looks tan. Blue-leaning light makes sand appear gray and causes alternate colors, particularly vegetation, to stand out.

StarHalo said:

Warm emitters are a must for power outage lighting; the cozy and welcoming fireside hue is a pleasant morale boost where it's needed, whereas using a clinical, sterile cool emitter feels like sitting in your garage.

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In your opinion.

I think what people are drawn to with tint is the apparent contrast it creates depending where it's used. As StarHalo mentioned, cool lights make objects stand out in desert environments because of the contrast in relation to the background color.

In the case of warm tints I think they're preferred in forested areas because the red bias of the light creates more contrast between the green foliage and other objects. Whereas with a cool light greens and browns seem flat.

With that said it comes down to subjective preference, but it seems people have a preference for warmer light overall. I haven't encountered many homes where 6500k daylight bulbs are in use.

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In my limited experience I've found that all tints have their place (except 2,700K or less). I generally prefer cool white, but define exactly what that is as some of my 'cool whites' are perfectly neutral. No blue, no yellow, no nothing but pure white.

I recently purchased a terralux tle-31M and it is the best tint for outdoor use. Better than any of my neutrals and by far the most excellent to resolve the colours of nature, at least where I live.

4,500K to 5,500K is where I'm happiest. Either side of that and I could take it or leave it. In the end if you've got light when you need it, that's what matters. As mentioned above, 6,500K is horrible for home use. All my led lights in the house are usually 4,500K (some 5,000K) and it's just right. Better than the yellow halogen bulbs by far.

When I BBQ at night, checking the meat with a warm tinted light gives me far better results than a cool tinted light. The colors jump out better and I can get a better feel as to how far along I am in the cooking process. Same goes with computer repair, I can judge cable colors with both warm and cool tint, but my eyes are far more relaxed using warm or neutral tints. But that's just me. We're all wired differently, so to each their own in the end.

A bit OT, but I got one of these multiple led reading lights as a Christmas gift. I find I cannot use it for long. It washes out all the colour and makes the contrast between the ink and paper much reduced. I've gone back to my incan light that shows black on white print and much better colour. So I tend to believe the 'CW for throw, and NW for colour/contrast perception' rule is true.

LedTed said:

I've researched CPF about this point. As DM51 wrote, "It is very subjective."

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What's not subjective is that warmer tinted LEDs tend to have a higher CRI rating and offer better color rendering than cool white which leads to improved depth perception and object recognition (for example, a brown rabbit in a green bush will be virtually invisible when illuminated by a cool white source but easily distinguishable under warm white). So while it does ultimately come down to personal preference, there is still an objective case to be made in favor of warmer tints.

the.Mtn.Man said:

What's not subjective is that warmer tinted LEDs tend to have a higher CRI rating and offer better color rendering than cool white which leads to improved depth perception and object recognition (for example, a brown rabbit in a green bush will be virtually invisible when illuminated by a cool white source but easily distinguishable under warm white). So while it does ultimately come down to personal preference, there is still an objective case to be made in favor of warmer tints.

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Nope, that's subjective as well....as warm does not equal higher CRI. Some are confused, because some high CRI lights are warmer, and the actual wavelengths of the light emitted is not really measured by the kelvin scale which ONLY APPLIES TO WHITE LIGHT, such as from the SUN.



So, some things are done better with warmer light, and, some people prefer the look, and, other things are done better with a cooler light, and, some people prefer the look.


The other factor that can come up is the loss in actual output for a warmer LED.

All things being equal, the warmer version of a given LED will produce fewer lumens, and, have proportionally less range.


So, while I, personally, have a subjective preference for warm tints, I use lights for work, and, most of the time, I use the cooler tints because the work better. I have high CRI lights for when that function is more critical, but, generally, its better to actually be able to see something I'm trying to find, that to be able to find a matching color chip to go with it.

For example, 365 nm UV is very useful if something might fluoresce, or, not fluoresce relative to a fluorescent background, etc...but the CRI is not a relevant spec. I might use a yellower beam if that is advantageous, but, yellow light changes colors too, so, some colors will be seen worse in yellow light, and others will be better. As, for me, its about finding things more than saying their color is a particular shade of chartreuse, so, output trumps color rendition most of the time....from a performance perspective.


Again, the kelvin (Kº) scale is not meant to describe how yellow a beam is, its meant to describe white light, not colored light. Its grossly misused/misunderstood...and is often confused with CRI, etc.


So, its completely subjective...and, that forces me to use what works best, which is often a cooler version of a light, even though I prefer the warm look.


So I might HAVE a warm version and a cool version of the same flashlight, and use whichever version makes sense at a the time.


For example, I have a flashlight that has a Nichia219 version and an XML2 version, and the the N219 is a high CRI, with a yellow beam...and the XML2 has a cool white beam...and if I am looking for a lost person, I will use the XML2 version of that light, as I won't see as much of what's out there with the N219 version. (But, I still HAVE the N219 version...for when I can use it w/o compromising job performance)

Just echoing what everyone else has said. Coolish blue tints tend to make better uitility lights when you just need to light something up, but they do tend to make everything look flat. Almost 2 dimensional. I have a preference for warm tints, particularly the warm high cri xpg emitters. To me they give everything a more 3 dimensional depth and more color. In addition the warm tints give me that cozy feeling instead of a clinical, cold feeling. So I guess it's not just the depth and the color but also the perceived "feelings" you get from a particular tint as well. I know that after using a warm tint for a while the white balance in my brain makes it look white instead of warm. It's gotten to the point that I turn them on and think I accidentally picked up one my cool tinted lights. Then I turn on a cool tinted light that I thought was white and it looks as blue as a blue led can look until my white balance corrects it back to white again. Most house lighting is a warm tint almost identical to a high cri xpg emitter, which I suppose is what they were going for, so I find it odd that so many people hate a warm tint when it's the same tint as the indoor lighting that they've lived under all their lives.

All personal preference.

TEEJ said:

Nope, that's subjective as well....as warm does not equal higher CRI. Some are confused, because some high CRI lights are warmer, and the actual wavelengths of the light emitted is not really measured by the kelvin scale which ONLY APPLIES TO WHITE LIGHT, such as from the SUN.

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You need to read what I actually wrote, because I never equated color temperature with CRI. Rather, I said that "warmer tinted LEDs tend to have a higher CRI rating", which is an objective and true statement, and while the sun is a full-spectrum light source, the vast majority of cool white LEDs are not and generally have an inferior CRI rating compared to their warmer counterparts.

I will agree, however, that cool white emitters often do have a higher raw output, but the difference in real world applications is often negligible. For one thing, you need a 4x increase in output for there to be a perceived doubling in brightness, so the difference in brightness between a 120 lumen warm emitter and a 200 lumen cool emitter might look significant on paper but is slight in practice. Secondly, even with a lower output, the superior color rendering often found in warm white emitters allows you to better perceive details in the environment. So while a cool white emitter might be theoretically brighter, you can actually see better with a warm white source.

Finally, CRI is not based on white light, it's based on a black body radiator at the same color temperature. Believe it or not, a candle has a CRI rating of 100.

Just last night I was glad that I grabbed an N219 light because while in the yard we harvested some kumquats, and we could tell which were ripening with the neutral hi-CRI beam. I actually pulled out my peak cool-white to try that as well and we could not distinguish the fruit colors very well at all. Quite a dramatic difference in utility!

the.Mtn.Man said:

What's not subjective is that warmer tinted LEDs tend to have a higher CRI rating and offer better color rendering than cool white which leads to improved depth perception and object recognition (for example, a brown rabbit in a green bush will be virtually invisible when illuminated by a cool white source but easily distinguishable under warm white). So while it does ultimately come down to personal preference, there is still an objective case to be made in favor of warmer tints.

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I fully agree with this. As well stated CRI of different LEDs and my own experience of several flashlights confirms it. In most cases a warmer LED provides better color rendition than a cool LED. The example with the rabbit is excellent. Also when comparing blue and purple colored objects I have found that warmer tints usually better separate the different shades. A cool LED often makes purple to look almost the same as blue, while a warmer tint actually makes the purple hint more visible, though not as good as an incandescent light. Actually I find the color rendition of my 4000K XP-G2s and XM-L2s close to Nichia 219 while the difference to cool LED is huge.

TEEJ said:

Nope, that's subjective as well....as warm does not equal higher CRI. Some are confused, because some high CRI lights are warmer, and the actual wavelengths of the light emitted is not really measured by the kelvin scale which ONLY APPLIES TO WHITE LIGHT, such as from the SUN.

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It may be that warm tint in it self does not equal higher CRI. Yes, the sun is a great example. Still, when it comes to the actual LEDs used in flashlights it's the common case. And I think that is what's really matter if we are talking about just the actual LEDs used in flashlights.

Swedpat said:

The example with the rabbit is excellent.

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That comes from my actual experience. I was in my backyard garden one night comparing a cool white HDS Rotary to my new high CRI warm white HDS Rotary. I first tried the cool white and observed the color of the foliage, then I turned on the warm white, and suddenly, there's a brown rabbit staring back at me not more than three-feet away. It actually perplexed me that I had missed seeing something so obvious, so pulled out the cool white again and realized that the rabbit's brown fur became virtually indistinguishable from the green backdrop he was sitting in front of. I was quite an eye-opening demonstration.

If I want to fall asleep about two hours from now, I use an amber LED -- which doesn't emit in the 400-500nm band that controls the circadian clock system (the effect is less strong for mid-adult age whose sleep is less easily disturbed; it's stronger for babies and older people whose sleep cycles are already less consolidated and more easily disrupted)


Here's a nice warm yellowish LED flashlight -- Fenix TK20 -- with a significant blue emission in the spectrum: http://spectralworkbench.org/analyze/spectrum/19881

Here's a SK68 clone, very blue-looking -- also with a significant blue emission in the spectrum: http://spectralworkbench.org/analyze/spectrum/19899

Brasso said:

Coolish blue tints tend to make better uitility lights when you just need to light something up, but they do tend to make everything look flat. Almost 2 dimensional.

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I don't find that at all. My cool white lights give me the same depth perception as high CRI warm whites or neutral whites. The high CRI lights give me better color contrast, especially if they're warm tints and there's a lot of red hues in a scene. But as far as being able to tell if a rock is 10 feet or 15 feet away, no problem at all regardless of whether I'm using cool white or a warm incandescent.

My personal preference is a warmer tint, as long as it's "white" with a high CRI. But I'm okay with anything from 3500K to 5500K or even a bit higher. The sun is 5500K, so I don't find that unusually "cool white". Above 6500K and I really don't like the blue tint. Below 3500K is okay for mood lighting, but I find it difficult to distinguish blues if the light is too warm.

I prefer neutral to warm LED lights, but where they really make a huge different to me versus cool and/or bluish LEDs is outdoors at night. With neutral or warm LEDs or incan lights, the woods look more natural and three dimensional to me. With cool/bluish LEDs, the woods look flat and two-dimensional. YMMV.

Etsu said:

The sun is 5500K, so I don't find that unusually "cool white".

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As noted, the sun is a full spectrum light source. The majority of cool white LEDs are not, so it's a rather useless comparison.

On the topic of depth perception, it's not that I can't perceive depth with a cool white source but rather I feel like my eyes have to work harder to see it, but I recognize that this may not be true for everybody.

the.Mtn.Man said:

As noted, the sun is a full spectrum light source. The majority of cool white LEDs are not, so it's a rather useless comparison.

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It's not a useless comparison at all. All manufacturers use color temperature to reference their lights. The color temperature refers to the temperature that a black-body radiation source (I.E., THE SUN) would emit light that matches the color profile of the light.

The fact that the sun is a full-spectrum black-body source of light refers to its high CRI, not the color temperature.

If you don't believe me, shine a bright cool-white LED (with a color tint around 5500K) at a spot of white carpet that the noon-day sun is shining on. It will look the same color.

The spectrum of the light becomes meaningful for accurate color rendition. But you can have a horrible spectrum of light (with regards to distinguishing color) and it can still look white like the sun. So the choice between "warm" and "cool" is simply a tint preference.