Ir cut filter for lights

Fred

Does anyone have any experience cutting the IR content from incandescent lights. I have to use a kinect for skeleton tracking and need super fast pickup of skeletons. I noticed the or content of normal stage lights slows this down by confusing the time of flight system. I can easily fins solutions for going the other way (cutting visible light and passing IR) but the opposite seems harder, well much more expensive to achieve.

mark

I have nothing to offer. @Bodo? Do you know anything about IR-cutting filters on lights?

Best Wishes,

Mark

CraigAlfredson

Try Roscolux 1995

[Rosco website](http://rosco.com/filters/roscolux.cfm#colors)

vanakaru

If you could use filter on Kinect then there are filters for cameras that cut IR.

http://www.ebay.com/sch/i.html?_sacat=0&_nkw=ir+blocking+filter&_frs=1

http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xir+cut+filter&_nkw=ir+cut+filter&_sacat=0&_from=R40

Fred

@vanakaru The kinect needs the ir output and camera to work. I need to cut the IR from lights to stop that interfering with the kinects IR.

@craigAlfredson This is actually pretty close, have you tried it?

hallo. you can use lee 269 heat shield. it filters out nearly 90-95 % of heat=ir rays.
maybe u can use two layers.
r.

eMTv

@deflost said:

you can use lee 269 heat shield. it filters out nearly 90-95 % of heat=ir rays.

Just discovered these heat shields while trying out GBRR gels sandwich to create IR light on traditionnal lighting devices today, and didn't see any change in the amount of IR emitted ?

It's supposed to help reduce the heat and protect the gels without changing their (visible) color.I don't know how it works, but from what I experienced, it doesn't cut IR rays (which is very good for my usage).

@mark, I'm surprised you didn't mention these at all, when talking about creating Infra-Red in the 10k-views tutorial about IR Tracking on the Isadora channel ? Have you ever tried that for 16 [R]evolutions (in order to reduce the amount of burnt gels, or increase their lifetime...)?

I'd be interested to have some feedback from you all, if you have some experience with it, because during our first tests, we didn't go for long sessions in a row, so that we wouldn't burn the gels too quickly, and therefore I can't really say anything about the amount of heat reduction in this 4 gels sandwich setup, but I definitely didn't see any change in the amount of IR captured by the camera..

Any thoughts ?

Kathmandale

Heat shield is really effective. If you’ve not used it before though there is one golden rule. There has to be an air gap between the shield and the dark gels/filters you’re protecting, the bigger the better. It can be a few millimetres, say with gel held perfectly tight in frames in separate slots. That will work and you will see an improvement. But if you can increase that gap, ideally by getting the dark colours further from the light source, then you’ll get better results. It’s tricky to do this on profile/lieko type units. On fresnel/pc/flood/parcan type units a good method is to use is to put the heat shield in the normal gel-frame slot and to tape the dark gels to the barn-doors. You have to use much bigger cuts of the colours but they’ll last a lot longer. A lot of tv and film type lighting use this method all the time. Make sure you’ve got heat proof tape though, matt black ‘black-tak’ aluminium tape is perfect but expensive. You can also use cheap plumbers aluminiuminsulation tape, it’s silver so looks ugly but does the job just as well if looks aren’t a concern.

A final trick is to consider how the lights are focused. With fresnel/pc type units you adjust the spot/flood by physically moving the lamp closer to the lens. A fully flooded unit will have the lamp as close to the lens as possible meaning the heat is much much more direct as there’s less of an air gap between the heat source (the lamp) and the gel/filters. Refocusing slightly, moving the lamp back from the lens just a small amount, can have a big impact on gel/filter life time. You won’t be able to light such a wide area of course, but 4x not-quite-full-flood fresnels would be a better option than 3x full-flood fresnels covering the same sized area.

It’s a bit trickier with profile/zoom units as you’re moving the lens rather than the lamp, but the basic principle is try to focus with the lens further from the gel. Here the trick is more that a wider focus helps dissipate the heat over a larger area of the gel.