Barry, you once posted "tungsten-ish and daylight-ish colors". I've seen ones advertised with different coloring ratings, 2700k, 3200k,5600k. Are the color ratings for compact fluorescents just rough estimates? Some are dimmable, does that change the color temps much on these bulbs?
Compact Fluorescent question
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J_Barnes
Veteran
Re: Compact Fluorescent question
Typically, even if a flourescent bulb is rated for a specific kelvin color temperature, it's a discontinuous spectrum of light. Meaning there can be huge gaps in the color spectrum, or large spikes at certain parts of the spectrum (ie- green).
The classic "cool white" bulb from sylvania? is rated at around 5600k...but it has a huge green spike that shows dramaticly on film (not as much on video).
Also, the dimmable bulbs don't change color temperature, that's a characteristic unique to filamented bulbs like tungstens.
I think I might have just made up that word...filamented, but you get my point.
Typically, even if a flourescent bulb is rated for a specific kelvin color temperature, it's a discontinuous spectrum of light. Meaning there can be huge gaps in the color spectrum, or large spikes at certain parts of the spectrum (ie- green).
The classic "cool white" bulb from sylvania? is rated at around 5600k...but it has a huge green spike that shows dramaticly on film (not as much on video).
Also, the dimmable bulbs don't change color temperature, that's a characteristic unique to filamented bulbs like tungstens.
I think I might have just made up that word...filamented, but you get my point.
Barry_Green
Moderator
Re: Compact Fluorescent question
Yeah, color temperature is one factor, but you also want to look for a decent CRI (Color Rendering Index). The higher the index, the more "full spectrum" the lights are (i.e., less green spike, etc).
http://www.fullspectrumsolutions.com advertises "full spectrum" daylight bulbs with a CRI above 90. They only offer daylight color. I've got a few, tried 'em, and they're okay, but they're not pure 5600k, there is still a green spike in 'em.
TCPI makes SpringLamps that you can get in a variety of color temperatures, 3100 or 3400 would serve well as tungsten. They say their CRI is 84, but in testing against the fullspectrumsolutions lamps, I'd say they're about equal.
I've even got one of the dimmables, but I didn't test its color temperature difference when dimmed. I'd vote with J_Barnes that it doesn't change color.
About the green spike: J_Barnes hits it right on the head (as usual): the spike is MUCH more noticeable on film than it is on video. Even on the video preset the bulbs look fairly white when shooting something white, but on film there is a quite noticeable green tint. And on video you can white-balance to these lamps to eliminate the green cast, whereas with film I found I had to use a full MinusGreen to get it corrected... but on video, even with the preset, when I used the MinusGreen gel, everything looked purple...
Yeah, color temperature is one factor, but you also want to look for a decent CRI (Color Rendering Index). The higher the index, the more "full spectrum" the lights are (i.e., less green spike, etc).
http://www.fullspectrumsolutions.com advertises "full spectrum" daylight bulbs with a CRI above 90. They only offer daylight color. I've got a few, tried 'em, and they're okay, but they're not pure 5600k, there is still a green spike in 'em.
TCPI makes SpringLamps that you can get in a variety of color temperatures, 3100 or 3400 would serve well as tungsten. They say their CRI is 84, but in testing against the fullspectrumsolutions lamps, I'd say they're about equal.
I've even got one of the dimmables, but I didn't test its color temperature difference when dimmed. I'd vote with J_Barnes that it doesn't change color.
About the green spike: J_Barnes hits it right on the head (as usual): the spike is MUCH more noticeable on film than it is on video. Even on the video preset the bulbs look fairly white when shooting something white, but on film there is a quite noticeable green tint. And on video you can white-balance to these lamps to eliminate the green cast, whereas with film I found I had to use a full MinusGreen to get it corrected... but on video, even with the preset, when I used the MinusGreen gel, everything looked purple...
Re: Compact Fluorescent question
So even to try an gel them you still get a color shift. What Im trying to find is a low cost bulb to replace in my chinese lanterns and use as practicals. The photofloods are not very cost effective as a ligthing tool given I end up spending 40 - 60 dollars sometimes for a day of inddor shooting. Any suggestions for a high wattage tungsten bulb that could be some what corrected gel wise or with white balance and post color correction.
What do you consider shooting with the dvx then? Since its a video camera shooting a film curve would the green spikes be evident as if I where shooting onto real film?
So even to try an gel them you still get a color shift. What Im trying to find is a low cost bulb to replace in my chinese lanterns and use as practicals. The photofloods are not very cost effective as a ligthing tool given I end up spending 40 - 60 dollars sometimes for a day of inddor shooting. Any suggestions for a high wattage tungsten bulb that could be some what corrected gel wise or with white balance and post color correction.
What do you consider shooting with the dvx then? Since its a video camera shooting a film curve would the green spikes be evident as if I where shooting onto real film?
Barry_Green
Moderator
Re: Compact Fluorescent question
Perform a manual white balance and there are no green spikes.
High wattage tungsten, in a chinese lantern, = fire hazard. Look at the compact fluorescents, you can get a 55w or 65w, which is about 250 to 300 watts worth of tungsten, but with very little heat. Just do a manual white balance to overcome any spike.
Perform a manual white balance and there are no green spikes.
High wattage tungsten, in a chinese lantern, = fire hazard. Look at the compact fluorescents, you can get a 55w or 65w, which is about 250 to 300 watts worth of tungsten, but with very little heat. Just do a manual white balance to overcome any spike.
J_Barnes
Veteran
Re: Compact Fluorescent question
A flourescent bulb is an inherrently soft source, and a chinese lantern is an inherrently soft "filter" around your light source...softening a soft source leads to some compounding light loss and a luminosity that is probably unsuitable for your purposes. So you wouldn't want to use a flourescent inside a chinaball.
The real question is what kind of chinese lanterns are you using? If you tossed those lanterns near a candle, would your house burn down? The answer is probably yes, and thus that might indicate that they're not suitable to use with a large tungsten light source.
That being said, I've used some large china balls 2 ft+ in diameter with Photoflood bulbs successfully. Photofloods are daylight or tungsten balanced screw socket bulbs in the 250 to 300 watt range (as barry stated above). They get very very hot, so there is indeed a high potential for fire, so I try to use flo's whenever I can as a soft fill. Also, a large majority of the hanging screw-bulb type fixtures on the market today are rated for either 60 or 100 watts max. Putting a 250 watt bulb in an under rated socket has a good chance of melting the housing and causing a fire.
I don't have much experience with the screw socket enclosed dimmer flourescent bulbs, so I can't attest to any CRI numbers for them. Generally I like my practicals to be warm toned though, so a daylight balanced bulb wouldn't work in my lighting schemes.
A flourescent bulb is an inherrently soft source, and a chinese lantern is an inherrently soft "filter" around your light source...softening a soft source leads to some compounding light loss and a luminosity that is probably unsuitable for your purposes. So you wouldn't want to use a flourescent inside a chinaball.
The real question is what kind of chinese lanterns are you using? If you tossed those lanterns near a candle, would your house burn down? The answer is probably yes, and thus that might indicate that they're not suitable to use with a large tungsten light source.
That being said, I've used some large china balls 2 ft+ in diameter with Photoflood bulbs successfully. Photofloods are daylight or tungsten balanced screw socket bulbs in the 250 to 300 watt range (as barry stated above). They get very very hot, so there is indeed a high potential for fire, so I try to use flo's whenever I can as a soft fill. Also, a large majority of the hanging screw-bulb type fixtures on the market today are rated for either 60 or 100 watts max. Putting a 250 watt bulb in an under rated socket has a good chance of melting the housing and causing a fire.
I don't have much experience with the screw socket enclosed dimmer flourescent bulbs, so I can't attest to any CRI numbers for them. Generally I like my practicals to be warm toned though, so a daylight balanced bulb wouldn't work in my lighting schemes.
Re: Compact Fluorescent question
Sorry I didn't expand on the chinese lanterns. I'm using 12 inch white arcrylic plexiglass light post globes as lanterns. All the sockets and wiring I did myself, they can handle I think up to 500 watts tungsten. I used to use paper lanterns, but they turned darker after age and usage where the globes stay white, though they dont fold up like a paper lantern. I was thinking of trying the CFLS because the cost of practicals and the 4-5 hours I get out of them is killing me.
Sorry I didn't expand on the chinese lanterns. I'm using 12 inch white arcrylic plexiglass light post globes as lanterns. All the sockets and wiring I did myself, they can handle I think up to 500 watts tungsten. I used to use paper lanterns, but they turned darker after age and usage where the globes stay white, though they dont fold up like a paper lantern. I was thinking of trying the CFLS because the cost of practicals and the 4-5 hours I get out of them is killing me.