Warm vs cool tint???

[Brian321]

I am just wondering the difference between the two? Like how much brighter is a cool tint over a warm tint(same flashlight/ Lumen rating)? Thanks.

Also which would be better for caving?

 

[Moonshadow]

Brian - this is perhaps one of the most commonly-debated topics on here.

There's a bunch of threads here to get you started:

http://www.google.com/search?q=Warm+vs+cool+tint&sitesearch=candlepowerforums.com

Like how much brighter is a cool tint over a warm tint(same flashlight/ Lumen rating)?

That's a bit like asking which is heavier - a pound of nails or a pound of feathers. Lumens are how overall brightness is usually measured, so two identical lights with the same lumen rating should appear equally bright. The warmer tint LEDs are generally available in slightly lower output ratings than cool tints though, so typically the warm variant of a given light will have a slightly lower lumen rating than the cool version. This is simply a function of the phosphor having to convert more of the blue light to longer wavelengths.

 

[Outdoors Fanatic]

Oh no, not again...

 

[KarstGhost]

I prefer the neutral and/or warm colors better for caving.

When you're standing in chest deep, or ear deep water in a cold cave the cool blue LED's don't feel very friendly.
I think the neutral colored LED's are awesome for caving with their friendly colors like an incan, but longer run-times.

Brian123, have you ever been caving with carbide? It is the most happy/friendly light source for cold caves.

 

[Swedpat]

According to as well my and others experience the usual better color rendition of warm LEDs in many cases more than weigh up for the slightly lower output. And I am really sure that it's better for caving as well.

Regards, Patric

 

[Wattnot]

Oh no, not again...

I honestly didn't know this was a big controversy. To me it's a simple trade off. A few lumens for a nice tint. Are people arguing about the usefulness of the neutral light in actual use? Has anyone done any real testing to see if:

A. Color rendition matters
B. If yes to A, do the neutral LEDs emulate a true incan enough?

I hope I don't aid in the horse beating . . . I never participated in the other threads. I never even noticed them!

 

[hoongern]

I honestly didn't know this was a big controversy. To me it's a simple trade off. A few lumens for a nice tint. Are people arguing about the usefulness of the neutral light in actual use? Has anyone done any real testing to see if:

A. Color rendition matters
B. If yes to A, do the neutral LEDs emulate a true incan enough?

I hope I don't aid in the horse beating . . . I never participated in the other threads. I never even noticed them!

If you want the 'true and solid numbers',

Neutral LEDs and Cool LEDs from the Cree XP-E/XR-E etc are the same, i.e. Neutral LEDs do not have higher color rendition than Cool LEDs.

(Check Cree's documentation --> http://www.cree.com/products/pdf/XLamp7090XR-E.pdf)

Typical CRI for Cool White & Neutral White (3,700 K – 10,000 K CCT) is 75.
Typical CRI for Warm White (2,600 K – 3,700 K CCT) is 80.

So it boils down to a couple things:

1) If you favor cool tints and high CRIs, get a high CRI, cooler CCT emitter. (I don't think they exist > 6000K)

2) If you favor warm tints and high CRIs, get a high CRI, warmer CCT emitter.

3) If you don't care about CRI, then choose either warm or cool as you like.

CRI and tints (warm, cool) are two different matters. For example, the Cree 4000K tints are only 75 CRI, while the Seoul 4000K tints have 93 CRI. Huge CRI difference, while their tints are exactly the same. Meanwhile, the Nichia 083 has an even cooler 5800K tint, but has 96 CRI (Look at McGizmo's Sundrop).

Here are some good threads:
http://www.candlepowerforums.com/vb/showthread.php?t=239966 (McGizmo's Sundrop XR-U)
http://www.candlepowerforums.com/vb/showthread.php?t=255770 (Any production Nichia 083 high CRI lights?)
All preference

 

[Buck_Naked]

Has there been any comparison testing of the different tints under certain environmental conditions, such as fog, mist, rain or smoke?

I have at times found an incandescent with a warmer tone seemingly 'penetrate' certain environmental conditions better than a cooler tinted LED, and have wondered if its the tint or some other factor involved that has given that impression.

 

[dymonite69]

so two identical lights with the same lumen rating should appear equally bright.

But visual sensitivity is not equal across the EMR spectrum. Our vision is most sensitive at 550nm (yellow-green)/

 

[Moonshadow]

But visual sensitivity is not equal across the EMR spectrum. Our vision is most sensitive at 550nm (yellow-green)/

Lumens are already weighted to take this into account:

The lumen (symbol: lm) is the SI unit of luminous flux, a measure of the power of light perceived by the human eye. Luminous flux differs from radiant flux, the measure of the total power of light emitted, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light.

http://en.wikipedia.org/wiki/Lumen_%28unit%29

 

[dymonite69]

Lumens are already weighted to take this into account:
http://en.wikipedia.org/wiki/Lumen_(unit)

But what happens when the spectral power distribution of the test source is non-normal?

 

[Moonshadow]

I'm not quite sure what you are asking now.

The original question was which of two lights with the same lumens would appear brighter. Since lumens are a measure of perceived brightness then pretty much by definition the only sensible answer is that they would appear equally bright.

 

[dymonite69]

I'm not quite sure what you are asking now.

The original question was which of two lights with the same lumens would appear brighter. Since lumens are a measure of perceived brightness then pretty much by definition the only sensible answer is that they would appear equally bright.

Not as I understand it. Subjective brightness, luminance and luminous flux are not synonymous. What eyes sees and what the lux meter measures are different.

http://www.crompton.com/wa3dsp/light/lumin.html

http://gaia.lbl.gov/btech/papers/25174.pdf

 

[kramer5150]

I am just wondering the difference between the two? Like how much brighter is a cool tint over a warm tint(same flashlight/ Lumen rating)? Thanks.

Also which would be better for caving?

Threads like this are fun because they really depend on the visual capabilities and preferences of the individual.

I have always found colder tints brighter "looking", just casually shining them around. But when I try and focus my vision on small details in the field of view, I always have to strain using the brighter cold tints.... squint and really bear my focus down on the object downrange. As opposed to warm tints, where I do not have to do that, I can just comfortably (without strain) look at the objects and see smaller details.

Its even a step further with incan and 5000K HID (warm tints and high CRI being the advantage).

 

[dymonite69]

I have always found colder tints brighter "looking"

As opposed to warm tints, and see smaller details.

Our vision works differently at different light levels. In low lighting our rod cells are activated. They are good at picking up light but more sensitive at shorter wavelengths (blue) then cone cells. This is at the expense of spatial resolution and colour perception so we can't pick up details or discriminate colour very well.

At higher light levels the cone cells predominate in light processing. They require more light to function with a peak sensitivity in the yellow-green spectrum. Visual acuity and colour discrimination is excellent.

In other words, in normal light we see high definition colour TV and in low light we see grainy black and white.

Somewhere between the two lighting levels there is a mixture of effects.

The wavelength sensitivity of the eye is optimised for daylight. The sun stimulates the three types of colour receptors in equal amounts such that we perceive a neutral colour - white. Most other artificial light sources can't reproduce this effect (except incandescents and halogens) and thus altering the perceived colours that we would normally experience under natural lighting conditions.

 

[dymonite69]

Another interesting article that explores this in more detail:

Night Vision

The bottom line is that you need to choose your colours and brightness levels carefully depending on what you are trying to illuminate.

 

[mudman cj]

This thread is one of the best IMHO on the subject because the posts explore how the differences in spectral outputs of cool vs warm tinted LEDs affect our ability to perceive objects which they are illuminating.

The key to the discussion IMHO is that CRI isn't everything. Two LEDs can have the same CRI and yet one can be better for most individuals at providing a clear view of typical subjects as well as better depth perception. I recall reading that CRI is not meant to be used to compare two light sources with different CCT values, but now I can't find a reference. Regardless, I do not think that CRI is an accurate measure of color rendering ability even for light sources with the same CCT, and it certainly fails to address differences in color contrast. There is work underway to develop a new standard for color rendition which will be called the 'Color Quality Scale'. Here is a link to a paper on the Color Quality Scale.

The following image is an example of how CRI can fail miserably. This light source has a CRI of 82 and yet it renders red objects as brown. I obtained it from this source article. The point of the example is that some light sources with a lower CRI would fare better at rendering colors by way of opinion because our perceptions often disagree with the CRI method.

CRI really only measures the extent to which a light source is similar to an ideal source with the same CCT, but the ideal source itself may not render colors well if it has an extreme color temperature, such as having too much or too little blue or red.

I am in the camp of those that find neutral/warm tints better for general use for these reasons, and as has been said many times before, the difference is more apparent outdoors.

If you want to 'daze' someone with a light, then you would choose a cool white LED because the blue component is more effective at blinding someone and cool white LEDs contain a larger proportion of blue light than neutral or warm tints, plus of course they are also brighter to boot. I would select a neutral or warm tint for all other uses though based upon my experience using them in typical situations.

 

[alvin8803]

Hello, i'm a newbie here. How will i know if torch i'm going to get has warm tin or cool tint? Thank you.

 

[Flying Turtle]

For an unknown light it's probably safer to assume the tint will be cool, if it is LED. Warm tint lights are usually advertised as such. There will always be some variation, even between "identical" lights.

Geoff

 

[NightKids]

Get a cheap Quark Mini Warm for $39 and try it out to see if you like it.