Adjusting tint w/ filters...yay, or nay?

I used the search function, but didn't find a lot. I'm wondering how to best go about altering the tint of an LED, using a colored filter. I saw something once about using photographic filters. My hope would be to try making a cool white into something warm-ish, for better outdoor color, hopefully without losing too many lumens in the process.

Does anyone have suggestions on how to best go about this, attach a colored filter, etc., or is it a waste of time?

Cheers,

R.ticle One

I reccomend this alot................but usually for the various strengths of LDF in it but it will work for you too.
Roscolux sample pack.

LDF, red, green, blue, yellow, and everthing in between in many many strengths. If it can be done with a filter you'll find it in that pack.

Happy experimenting!

You'll loose a good bit of output. Swapping out the emitter for the tint you desire would be the most efficient and brightest option.

When you put a colored lens in front of a light, it works like a filter that only allows that particular color to pass through - all the other color is blocked. So if I put a red lens in front of a light source that has only 20% of its output in the red part of the spectrum, then my now-filtered light will only be 20% as bright as it was before.

The limitation lies in the LED itself; our common high-output cool white LEDs are excellent at emitting blue and yellow-green, but the rest of the spectrum is barely emitted at all. You might have noticed this when viewing different colors using your LED light, that some shades of blue and neon green/yellow almost seem to fluoresce as if under a blacklight, while any shade of red appears very muted, often shifted away somewhat towards orange. This is because of the limited-spectrum nature of the LED, it does a few colors very well and a few others poorly.

The new warm-tint LEDs have essentially the same spectral rendering but with a little extra orange/red thrown in. You can't reproduce this effect using a filter on a cool white LED, because the filter would *only let the lens color through* and block the rest.

Also keep in mind that tint and color rendering are two different things. An LED can have a warm tint and still have poor color rendering (meaning everything would look warmer compared to a cool white LED, but there would be no difference in what range/how many colors are rendered)

I have never tried it but, if it didn't significantly reduce Lumen output I might consider it. I only really "need" ~70 Lumens for most tasks anyways.

StarHalo said:

When you put a colored lens in front of a light, it works like a filter that only allows that particular color to pass through - all the other color is blocked. So if I put a red lens in front of a light source that has only 20% of its output in the red part of the spectrum, then my now-filtered light will only be 20% as bright as it was before.

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This is somewhat true but i think its a little misleading. I'm guessing that the OP was referring to the idea of making the beam more yellow/orange so it would be a warmer color. The way a filter would work in this case is that it would allow red, green, and orange light to pass through, which our eyes perceive as being yellow.

Therefore, its not as simple as saying that the spectrum has 5 colors and by blocking 4 colors to get the color u want, you will only get 20% brightness. In reality others colors are also passing through, giving you much higher than 20% of the original brightness. But the idea of what your were saying is correct, that you lose a lot of light by using a filter.

i do just that for my Pelican M6. i use Cokin photographic filters 81B & another 81D when they get scratched up.

warming filters do not reduce output by too much, that i am being very partial. and Cokin filters are surprisingly easy to file to size. i wonder if photographic equipement stores are so kind to let you folks shine your lights through the filters? the shop i frequent let me do just that before i bought the filters. they were rather amused.

81A (lightest tint)
81B (darker than 81A)
81C (darker than 81B)
81D (darkest tint of the 4)

sepia filter on the other hand may be too dark, but there's a sepialight which may be of lighter tint.:shrug:

another option is to have them made at optical shops, multi-coated lenses are a more pricey option, but worth considering too.

I have tried using filters to "warmify" the output of cool white LEDs but the results are generally not good. Even relatively "gentle" filters still cause a lot of light output because of extra air-plastic interfaces that are introduced by adding a filter in front of your lenses -- this means more multiple reflectiosn and losses. The difficulty of cutting and mounting a filter in a light so that it were to look halfway decent, it would be just about as easy to simply buy a warm- or neutral-white LED and perform an emitter swap.

Another thing to keep in mind is this -- Ive find that when trying to make my cool emitters into warm emitters using CTO filters, that the eventual result is no a warm white, btu actaully yellow-greenish "pea soup" appearance. The cool white emittres have a serious lack of red light that becomes increasingly obvious as you filter the light to try to make it warmer.

On the other hand, If you were to buy a neutral or warm white LED, those are designed with different phosphor combinations that actually do generate a significant amount of red light. The drop in efficiency is also minimal by performing an emitter swap, whereas you might lose a very large amount with comparable filtering.

Hey guys, thanks for the thoughts on filters...I may check out that sample pack, thanks for that - however, it seems that it may be difficult to get the results I'd be after with a filter.

I agree, I'd love to just do an emitter swap, but the light that I'd really thought of getting (which has a cool white LED but seems perfect in every other way for what I want - the EagleTac P10A2) has a design which I've been told makes it nigh on impossible to swap it out.

What I'd hope for is a beam that has a pleasing tint - I know that's subjective - and good rendering...so not necessarily a beam that is simply warm looking.

sORe-EyEz, would you mind explaining how you mount filters on a light - and the process of a multi coated lens getting made? Like, would you get the lens cut from scratch, or modify something pre-existing?

Cheers,

R.ticle One

not sure about EagleTac P10A2 the Pelican M6 is a modular system that allows for replacement windows much like Maglite. that will be ideal, for non modular lights the only way fix the filters on is fiction fit. but replacing them will be a problem later.

i'll like to correct on the "sample packs" thing. i think there was a miscommunication on my part. but the retail assistant should be able to take out the filter for a test shot with the light, as i normally request to check he condition of the filter when buying for my camera.

as for multi-coating the plastic filters i was told by the optician it can be done at an extra cost, just like eye glass wearers. just specify that the plastic be made without degrees, best let them know its for flashlights. they'll understand not to curve the lenses too much that it alters the beam. :sick2:

from my understanding the EagleTac model is similiar to Fenix T1 on the bezel end? :candle:

I like the results of using a LEE Filters #152 Pale Gold to warm up the tint of my M60 to be closer to my M60W. I wanted to try #001 Sunset 1 since it said that it was good for balancing LEDs, but it wasn't in my swatches. The Roscolux #302: Pale ******* Amber may be a good choice also.

I removed the window from my 6P bezel, cut the filter material to the same size as the window, and install the window with the filter on the inside of the bezel.

The slight loss of output is more than made up for by the increase in usefulness of the warmer tint.

It's warmalicious!:twothumbs

I try to tell people it's an acceptable trade off!

What do you loose 5-10 lumens max and you get an eye pleasing light!

I have a DBS fitted with a Hoya Y2 filter. I was amazed at how bright it still was when I first installed it. The objective was to remove all blue & UV emissions in order to reduce wildlife disturbance

The interesting thing was that our own night vision improved, this in turn compensated for the ruduction in lumens, BTW the Tiablo on the right has a Cree XR Red Led fitted.

Sgt. LED said:

I try to tell people it's an acceptable trade off!

What do you loose 5-10 lumens max and you get an eye pleasing light!

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That would depend on your filter. Putting a red filter over a white LED for example will block 80-90% of the total output.

Thats correct, a red filter is useless compared to using a red emiter especialy when its overdriven a bit

R.ticle One said:

I'm wondering how to best go about altering the tint of an LED, using a colored filter. I saw something once about using photographic filters. My hope would be to try making a cool white into something warm-ish, for better outdoor color, hopefully without losing too many lumens in the process.

Click to expand...

Sgt. LED said:

I try to tell people it's an acceptable trade off!
What do you loose 5-10 lumens max and you get an eye pleasing light!

Click to expand...

Marduke said:

That would depend on your filter. Putting a red filter over a white LED for example will block 80-90% of the total output.

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You have made a true statement but nobody here wants to use a red filter or make a red tinted LED by using a filter........... We are only going from cool white to warm white.

I wonder what the best filter would be - I know that salmon colored filters are used to bring the very cold light of flashes to incan color. Otoh, a light yellow filter makes sense to reduce that really huge blue spike while letting through the other light. Well, looks like I'm making a trip to the next photo store tomorrow.

And Sgt. LED, I do
It's a win-win - 3 lumens of my D10 are sometimes way to much, plus I want to keep my scotopic vision.

balou said:

...a light yellow filter makes sense to reduce that really huge blue spike while letting through the other light.

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Just remember... yellow and blue make green :green:

Sgt. LED said:

You have made a true statement but nobody here wants to use a red filter or make a red tinted LED by using a filter........... We are only going from cool white to warm white.

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Even moving from a cool white to a warm white using filtering is MUCH less efficient than actually switching to an inherently warm white emitter. Using a lightmeter I've seen ~40% drop from a filter that brings my cool whites down to the neutral white range I'm looking for. The neutral whites, are only about 15% less power-efficient. Consider that even a completely "transparent" filter will have some additional losses due to adding more reflective interfaces between the LED, and the outside of the flashlight.

Not only that, the neutral whites tend not to be as red-deficient to begin with. In my experience heavily filtering cool white LEDs leads to a final product that looks yellow-green compared to an actual warm white emitter of the same color temp, because the warm has a phosphor emitting proportionately more red output.

That said, in cases where it's impractical to perform an emitter swap, or where you want the mod to be reversible, something like a snap-on "warmify" filter is not a bad idea. I personally at this point don't even buy cool white LEDs if I can avoid it, and have performed emitter swaps on all lights I regularly use.

2xTrinity said:

Even moving from a cool white to a warm white using filtering is MUCH less efficient than actually switching to an inherently warm white emitter.

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True but you can't always swap the emitter.

2xTrinity said:

Using a lightmeter I've seen ~40% drop from a filter that brings my cool whites down to the neutral white range I'm looking for. The neutral whites, are only about 15% less power-efficient.

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Some filters are way better than others. Shop around and test different brands.

2xTrinity said:

That said, in cases where it's impractical to perform an emitter swap, or where you want the mod to be reversible, something like a snap-on "warmify" filter is not a bad idea.

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Exactly :twothumbs I'd rather have all 5AQ3 emitters but not everybody is offering them yet. Eventually they will!