De-Greening Luxeons

My brother restores and refinishes crystal ware. He has some pieces on display we tried to light with some Luxeon Stars, unfortunately all I had available were some greenish P2s. Green my be an inconvienence in a flashlight but in crystal ware it is the difference between a thousand dollar V-ah-se and a twenty-five cent yard sale peanut butter jar.

Photographers use filters called Minus Green to balance and correct flouresent lights for film and video work. I had a piece of Rosco "Tough 1/2 minus green" and tried it out. The 1/2 minus green pulled the color of the lowend P2 up to about a mid P3 with only a lose of about 25%. Really impressive. I bought some 1/8 and 1/4 minus green from a local theater arts store and played with different combinations of filters, P2s and drives to make a set of five display lights that looked equally white and bright.





Next step was to perk up some flashlights. I cut a piece to fit the bezel of one of my Mags.



Works like this



The 1/2 minus green will pull an LS up about one bin number with a loss of about 20-25%, the 1/4 minus green, about half a bin number (loss 15-18%) and the 1/8 minus green can be used to fine tune arrays to the same color.

Now I can use most of the P1s and P2s in general use (presents, etc. ) flashlights without people asking why it is green and save the Q3s for my lights. This is going to be better than telling them that the eye is most sensitive to green and therefore the light is more efficient.

Wow, that's impressive! Great suggestion we could all use. Thanks!

This is great. I was just complaining about the R2H I got that turned out to have a green tint. I'm going to the camera store.....Oh, maybe I should call first. /ubbthreads/images/graemlins/rolleyes.gif

Time for everyone to turn those seconds into firsts!

Just a general question: What sort of prices are those filters?

Wow -- those filters produce some very nice results! You say that the 1/2 minus produces a loss of 20-25%. Are you talking about loss of light output?

Zelandeth

The filters come as a 24in X 20in (60cm X 50cm) sheet (enough to make about a hundred filters for a Mag) and cost $US6-7 each. They are available in the UK.

LukeK

As an old satellite engineer out of habit I expressed it as a loss, the spec says 75% transmission for the 1/2 minus green. The Rosco.com site has better spectral charts than those in the picture above.

Hmmmmm... maybe lux reading are in order? You photo doesn't look like a 25% loss, but I suppose it's hard to tell in a photo.

What a pain to find it on the site. Here's a link:

http://www.rosco-ca.com/products/filters/filters-cinegel.html#Fluorescent

Keep in mind that the eye's response to brightness is nonlinear. i.e. a difference in 25% is tough to see. /ubbthreads/images/graemlins/smile.gif

Hey guys,
I was told by a fellow CPFer in England, that if you write the company they will send you a sample booklet. Although the sheets would be small, I was advised that they would be big enough to do a small flashlight. I was also advised that he wasn't sure if they would ship to the U.S., but I think it's worth a try.

Hey, the head office is in Ontario! I'm gonna email them and see what happens.

Alright, email's off the Rosco. I'll see what happens.

I heard from Rosco. The customer service rep gave me this phone number 1-800-767-2669. The rep said that they would be able to help.

Chop - I'm in Scotland ...............thats like me saying you are in Canada....................(only joking /ubbthreads/images/graemlins/grinser2.gif /ubbthreads/images/graemlins/twakfl.gif /ubbthreads/images/graemlins/twakfl.gif /ubbthreads/images/graemlins/twakfl.gif

As well as Rosco, Lee and for U.S GAM, will have similar colour correction filters, commonly called gel:

http://www.leefilters.com/

http://www.gamonline.com/

Might be worth asking about offcuts from larger theatre suppliers, but perhaps unlikely in this particular colour as its a fluorescent correction.

Adam

Pops,

Stunning find! (and more questions people will be asking now when buying lights, whether it's new mods or resales: "Uh, is the lens Gel'd? And if so, uh, what rating is it -- 1/2, 1/4, or 1/8?"
/ubbthreads/images/graemlins/grin.gif

Also if used on an already white Luxeon, will it turn the beam color -- violet or something?

Mr Bulk

Actually it makes a good white bin 3 look like a blueish bin 4.

I would assume that 'half minusgreen' is the same as two sheets of 'quarter minusgreen'?

Therefore it seem like a better idea to buy the sheet of lower factor (say the eighth) an use a few sheets each time. This makes 'fine tuning' easy and it's not like you're about to run out of material......

Doug Owen