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Discussion Starter · #1 ·
Anybody here ever try using Rosco’s Bastard Amber film over the cover lens of a CW lamp to yield NW? Am thinking this might be a good mod to the Sofirn SP33V3.0 which reportedly is in the 6500K realm.

https://www.bhphotovideo.com/c/product/43684-REG/Rosco_RS0211_02_Filter_Bastard.html

Dunno whether the Bastard is clear or translucent, can’t tell from the product image.

There’s also Lee Filters, which doesn’t offer their products retail and whose dealer map is FUBAR:

https://www.leefilters.com/lighting/zircon.html

Used their Color Temperature (Mired Shift) Calculator to find the correct value for converting 6500K to 4000K, result of 96 mired shift yielded this match: Zircon Warm Amber 5 (O32) which looks very close to that Rosco Bastard. :D (← Amber Face)

https://www.leefilters.com/lighting/mired-shift-calculator.html

Of course applying a color filter to a CW lamp will lower its lumens but so would going to a warmer phosphor if such were available. And much cheaper and easier just to insert a polycarbonate film beneath the cover lens than to solder in a whole new emitter, if you could even find one that’s compatible [with Sofirn’s 3V FET driver].
 

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Discussion Starter · #2 ·
Update

Also came across this Rosco Cinegel #3442 1/2 Straw CTS Filter, which I think might be an even closer match to the Zircon Straw something. A little bit lighter shade than the Bastard Amber so less lumens lost, more subtle tint correction.

https://www.bhphotovideo.com/c/product/44228-REG/Rosco_RS344211_3442_Filter_1_2.html

Compare to Bastard Amber:

https://www.bhphotovideo.com/c/product/43684-REG/Rosco_RS0211_02_Filter_Bastard.html

So ordered them both. Should arrive this Tuesday, will see then how they compare on an old MagicShine Clone with a very strong blue tint (SP33 V3 hasn’t arrived yet.) Will have a lot of film left over so if anyone here would like some 1-1/2” squares or strips just PM me.

Now don’t all answer at once! :p
 

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I think it's kind of unlikely somebody on this forum has tried this so I'll just throw some thoughts out there.

IDK. I would prefer a somewhat lower color temp than 6500K, but that seems to be very common (also among auto LED headlight conversions) so my guess has been that it's probably cost-effective/efficient. These filter films are obviously for LED photographic lighting (spectra of the lights, etc) and I know even less about that. Of course with photos, you always adjust exposure anyway, so some loss of light is not really that consequential.

FWIW: I do know that LED spectra are consequentially different than black body radiators, which is what color temp is based on so color temp is an approximation for LEDs. And then there is metamerism, where two visually identical colors can have very different spectra. For fun, I like to point out that color exists purely as a perception in the mind and doesn't exist outside of that. One example is to look closely at something displaying as yellow on your RGB monitor and you'll see there are only red and green dots.

I'm interested to hear how it works out for you.
 

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Discussion Starter · #4 ·
Well the other use of color filters is in stage lighting, which is where I first ran across these — while searching for swivel clamps to mount flashlights to my bike. Ended up buying the two products from B&H Photo, they had the best prices.

Of course the way both people and cameras register color is relative. So when outdoors on a clear day we don’t notice the blue tint from the sky on each other’s faces because our brains correct the white point. Same for night riding with a CW lamp, the light pretty much just looks white to us until passed by WW headlights, then the blue tint becomes more obvious and the other vehicle’s lamps appear very yellow. Likewise if you take separate beam shots of CW and WW lights the results most often look quite similar because the camera automatically corrects the white point as well. But if you capture two lights together one might appear cyan and the other pink, because it is not possible to adjust for two different white points concurrently. So will take comparative testing to figure out which if either filter acceptably neutralizes the XHP50.2 6800K. Failing this, B&H does offer swatch books for cheap. Only problem is that the films are 1.25” wide so might not completely cover the inner diameter of the SP33 lens, would have to black out any little remaining gap.

https://www.bhphotovideo.com/c/product/45184-REG/Rosco_950SBCNG0103_Cinegel_Swatchbook.html

I’ve successfully corrected CW tints on various plastic LED bulbs and puck lights by going over them with a blend of yellow orange and red permanent markers. (Have even directly modded dedomed emitters with yellow-orange chromium oxide pigments, works like a charm.) Experimented with my CW MJ clone the other day by applying a diffusing film colored only with an orange marker because I didn’t have any fresh yellow at hand. As a result there was too much red in it, beam turned kinda raspberry. So probably some tone of light orange would have worked okay — have to remember to buy more Bics!

Just received notice the films are scheduled for delivery on Tuesday. Too bad the Sofirns haven’t even shipped yet, it’s been weeks since I ordered them from the USA warehouse.
 

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....There’s also Lee Filters, which doesn’t offer their products retail and whose dealer map is FUBAR:

https://www.leefilters.com/lighting/zircon.html

Used their Color Temperature (Mired Shift) Calculator to find the correct value for converting 6500K to 4000K, result of 96 mired shift yielded this match: Zircon Warm Amber 5 (O32) which looks very close to that Rosco Bastard. :D (← Amber Face)

https://www.leefilters.com/lighting/mired-shift-calculator.html

Of course applying a color filter to a CW lamp will lower its lumens but so would going to a warmer phosphor if such were available. And much cheaper and easier just to insert a polycarbonate film beneath the cover lens than to solder in a whole new emitter, if you could even find one that’s compatible [with Sofirn’s 3V FET driver].
Looking at the Lee Zircon filters I'd probably try the warm amber filter numbers 4-6 just in case I happened to not like it if I only bought one tint. Sold in 2' x 2' sheets. If not real expensive I wouldn't mind trying this idea out on the Fireflies E01 I have. Seems there is a dealer in my neighborhood. I might check this out. If it doesn't kill the throw I'd go with it. I think the #5 warm amber filter would drop my 5700K output down to 4600K if what the website claims are correct.
 

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Discussion Starter · #6 · (Edited)
Filters now scheduled for delivery today!

Cat I wonder if the dealer would allow you to test out samples of Warm Ambers on your Fireflies right at their location. Guessing they’d have swatch books there.

Think those Rosco filters I linked to above are very close to the Zircons you’re looking at.

If you’d like I can send you a 2” strip of both Bastard and Straw once I get them tomorrow. [EDIT: Later today!] Then if they don’t work exactly as you’d like and you decide to purchase a Zircon from your local distributor instead, you can send ME a strip of YOUR amber.

Sound fair? If interested PM me your mailing address. :)
 

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Well the other use of color filters is in stage lighting, which is where I first ran across these ...
Har! Last time I was on a stage they were still using limelights. Well, not really, but it was long before LED lighting. Of course we did use "gels"...

I'm following your endeavors with interest.
 

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Discussion Starter · #8 ·

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Sofirns SP33V3.0 I’m expecting.
Still no lights yet, what's up with that? I took my SP33V3 (with Action lens cover) on last nights ride and even though I was cranking the light up didn't mind the light quality. Still interested in how your filters end up working. I haven't tried my light without the lens cover yet but if its like my SD05 I'm a little skeptical that just improving the tint will fix its beam pattern issues.
Mole
 

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Discussion Starter · #10 ·
Yeah my Sofirns haven’t even shipped yet, even though they’re supposedly coming from a USA warehouse.

Wouldn’t expect the color correction film alone to do anything about the beam pattern either, Mole, unless it’s translucent rather than clear. Which is why I also purchased that d-c-fix Milky Privacy Film as a stick-on diffuser. Out for delivery today, woo hoo, and so are those Roscos from B&H.

The metallic orange DIY reflector shield on my MJ-808 clone worked well in compensating both for its blue tint and the lossy diffuser I’d also added. Hoping same kind of application will apply to the Sofirns too, if they ever get here.

Actually, I probably won’t mind the 6500K on the SP33V3, since the XHP50.2 they’re using now seems to be a lot less blue than the previous version. Only problem is, all the other lights selected for that bike are 4000K and different temperature LEDs side by side do seem to bring out the worst in each other. Was hoping to blend them together without conflict but turns out the Mountain-ark stage lighting clamps purchased to mount flashlights to the RANS chopper bars and fork are rather cumbersome and won’t exactly fit the way originally planned, D’oh!
 
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