Kino flo chromatospectrography

hugovillasmythe · June 21, 2005

I just wrapped a horrible shoot. I had an Aaton XTR 16, used vision 320 and a 1/8B. Pro mist.

It took place in a hospital hallway with no windows and I decided to use celing mounted kinos as my main light source.

It worked well with the set dressing and looked like hospital lighting (which was the point).

I used 3 banks of 4 lamps 4ft. long, all 3200K. It was a mess since none of the tubes looked Ok. Some appeared to the aye oto be "pinkish", others looked "blueish".

I also used two 4k PAR (DeSisti), two Joker 400w and one 1,200w PAR. I checked all ligths for frequency (since we shoot 24fps and 75fps) and for color temp. with my colormeter.

All HMI's read fairly close to spec. and I corrected them to from their origin to somewhere between 3200K-3800K.

When I went to correct the already messy Kinos I remembered they're "unreadable" with standard color meters, therfore, I read them anyhow, combined the lamps and they ended up looking (aparetn to the eye) and reading (minolta color meter) 3200K-3800K.

Yesterday, at the telecine room, I almost had a heart attack. All light from the kinos was green, I mean green as in "martians on earth" green. We managed to correct the first shoot (an actor walking under the first kino bank) but, when it came to the actor walking under banks 2 and 3 on the same shoot things got much harder.

Each kino was greener than the other.

Fortunatley the colorist was great and we had time, so we managed to match, dissolve, paste, gamma block, power window, diffuse and correct the hell out of the stock and it worked.

I proceeded to call the rental house, they're good friends and have a huge stock of kinos (about 100 4ft long lamps and 50 2ft plus some mini flos).

The owner was very nice and concerned about it -after all, I've been involved with his gear in some way for more than 14 years now- so he volunteered that maybe all his tubes need checking.

He asked me if I could do it and I said yes...

Is there an instrument, way, method, etc. that can correctly evaluate "discontinious spectrum" sources such as Kinos.

I think this could be helpful to others, not just me...

Walter Graff · June 21, 2005

MAny people have trouble with fluorescent fixtures such as kino. As nice as they are, they simply can not be trusted. I've seen their fixtures drift all over the place. Most folks complain about the pink tone. Actually I've had more consistent luck with flouros I make myself. Instruments, yes but you need a few thousand bucks and a computer. In the field, it can be a guessing game.

David Mullen ASC · June 21, 2005

I've never had color problems with Kinos to THAT extent. It sounds like someone was mixing up brands of tubes in your Kinos, from Optima 32's to Kino 32's, to Kino 29's.

I've been on shoots and found out that none of the Kinos had Kino tubes and the gaffer telling me it didn't make a difference. "Hey, but these are cheaper and they look close enough!"

Kinos will get greener if there is too much heat building up around the fixture, like when people box in the ends with blackwrap, etc.

I don't use Kino 29's much since they look pink to my eyes.

In an all Kino-lit environment, I generally don't have color problems. When mixed with other lights, I find that they are 1/8th of some gel correction off, i.e. the Kino 32's need a 1/8 CTO or 1/8 Minus-Green or something to match tungsten lamps better, or the Kino 55's need a 1/8 CTO to match an HMI.

I've only had real greeness problems when people have stuck non-Kino tubes in the fixtures like Optima 32's, Vitalites, Chroma-50's, etc.

Phil Rhodes · June 21, 2005

Hi,

About colour in fluorescents:

- They go purple when under run, or run with too high a voltage and too low a current, or soon after starting. Most dimmable ballasts, including Kino's, do this, and it also happens when running a 4ft fixture with the ballast set to 2ft. It's an artifact of the voltage being high enough that more of the energy goes into a corona around the heaters. This purple is a bluish, argon-discharge purple, not pink, and is caused by the argon gas in the tube which is present to ease starting. The tube's output must be balanced against this purple discharge but the purple glow doesn't change as much with discharge current as the UV emission which drives the white light, so it isn't linear.

- They go yellow when over run or run with too low a voltage and high current. This is effectively the opposite problem of the purple issue.

I would fervently hope that Kino's ballasts are smart enough to regulate tube current and avoid this, but it's not easy, and I could believe they're missing a trick somewhere. Also:

- Organic phosphors age. The widest-band phosphors age fastest, particularly if you bombard them with shortwave UV radiation. The red phosphors go fastest, which is why "white" LEDs slowly go aqua-ish over time.

- They can appear to go orange, especially when the heaters are driven hard at low discharge currents in an attempt to improve performance when dimmed a lot, which is of course when the heater glow.

So in short, have fun, but if you have a problem with light not being recorded as it appears, I'd say the fault was actually in the imaging system not the lighting instrument!

Phil

Walter Graff · June 21, 2005

"In an all Kino-lit environment, I generally don't have color problems. When mixed with other lights, I find that they are 1/8th of some gel correction off, i.e. the Kino 32's need a 1/8 CTO or 1/8 Minus-Green or something to match tungsten lamps better, or the Kino 55's need a 1/8 CTO to match an HMI."

I think you said it best here David. I find kinos or any other fluorescent from your local hardware store with a good color rendition work best by themselves and not in mixed situations with other fixtures of various types without some sort of correction. I never liked the light of a flouro on its own. Just don't like the way they throw photons.

timHealy · June 22, 2005

I just wrapped a horrible shoot. I had an Aaton XTR 16, used vision 320 and a 1/8B. Pro mist.
It took place in a hospital hallway with no windows and I decided to use celing mounted kinos as my main light source.

It worked well with the set dressing and looked like hospital lighting (which was the point).

I used 3 banks of 4 lamps 4ft. long, all 3200K. It was a mess since none of the tubes looked Ok. Some appeared to the aye oto be "pinkish", others looked "blueish".

I also used two 4k PAR (DeSisti), two Joker 400w and one 1,200w PAR. I checked all ligths for frequency (since we shoot 24fps and 75fps) and for color temp. with my colormeter.

All HMI's read fairly close to spec. and I corrected them to from their origin to somewhere between 3200K-3800K.

When I went to correct the already messy Kinos I remembered they're "unreadable" with standard color meters, therfore, I read them anyhow, combined the lamps and they ended up looking (aparetn to the eye) and reading (minolta color meter) 3200K-3800K.

Yesterday, at the telecine room, I almost had a heart attack. All light from the kinos was green, I mean green as in "martians on earth" green. We managed to correct the first shoot (an actor walking under the first kino bank) but, when it came to the actor walking under banks 2 and 3 on the same shoot things got much harder.

Each kino was greener than the other.

Fortunatley the colorist was great and we had time, so we managed to match, dissolve, paste, gamma block, power window, diffuse and correct the hell out of the stock and it worked.

I proceeded to call the rental house, they're good friends and have a huge stock of kinos (about 100 4ft long lamps and 50 2ft plus some mini flos).

The owner was very nice and concerned about it -after all, I've been involved with his gear in some way for more than 14 years now- so he volunteered that maybe all his tubes need checking.

He asked me if I could do it and I said yes...

Is there an instrument, way, method, etc. that can correctly evaluate "discontinious spectrum" sources such as Kinos.

I think this could be helpful to others, not just me...

<{POST_SNAPBACK}>

This sounds like a completely unusual experience.

Were they Kino bulbs? If not were they all the same brand and type bulbs? Or were they a mix of whatever the rental house had? Had the rental house mixed up the order and give you cool whites and warm whites or something? It happens. What was the condition of the heads and ballasts? Did you call Kino for some poosible reasons as to why this may have occurred?

All Kinos have a green spike and as David suggests, gets greener as they heat up wrapped in gels and blackwrap. They get hot enough to easily melt the black plastic crates if their is not enough ventilation. Walter is right as Kino 32's are more like 3500 and need a little correction or they look a little cool. K29's are like 3200. But green as in "Martian" green, sounds like something else had gone wrong on your shoot.

In general I would insist that all the bulbs be the same if they are rigged on a set like that.

A little off subject but...I'll always remember the day I set up two 2k tungsten fresnels, one on each side of a 4x8 poly bounce for Fred Elmes. One side of the card had a mole 2k and the other side had an Arri 2k. The Mole was distinctly warmer than the cooler Arri, even though both were tungsten. Fred mentioned he wasn't crazy about it so it never happened again. Ever since, I always go out of the way to group like items.

Edited June 22, 2005 by heel_e

David Mullen ASC · June 22, 2005

People will complain about HMI's not matching, but once I had a long steadicam shot down a hallway in an abandoned building and I lit it with a dozen tungsten 1K's and tweenies in a row shining through open windows and archways to create patterns of moonlight.

I put 1/2 CTB on each light and the end result was that nothing matched! The gels, which were a collection of scraps, were all over the map in terms of color, some were not only faded but some were greener.

Had to get out a new roll of 1/2 CTB and cut new gel for all the lights from the same roll. And even then, there was mismatching in warmth from the various lights.

Sam Wells · June 22, 2005

A little off subject but...I'll always remember the day I set up two 2k tungsten fresnels, one on each side of a 4x8 poly bounce for Fred Elmes. One side of the card had a mole 2k and the other side had an Arri 2k. The Mole was distinctly warmer than the cooler Arri, even though both were tungsten. Fred mentioned he wasn't crazy about it so it never happened again.
<{POST_SNAPBACK}>

He's way too honest :D

A lot of DP's would drop a single in the Arri and say "see how it feathers into a cooler fill on the left"

-Sam

Phil Rhodes · June 22, 2005

Hi,

On that 16 I shot, the HMI (via CTO) was green.

Feh...

Phil

hugovillasmythe · June 23, 2005

Kinos will get greener if there is too much heat building up around the fixture, like when people box in the ends with blackwrap, etc.

This seems to be one of the probable causes for the mess I walked into. I did place the tubes inside celling mounted fixtures and then boxed in the lights further by black wrapping the long sides so they would fall off the walls.

However, I had done this before and never experienced such problems... or I did, but it didn't matter because the only light source I had in that shoot were two 4ft 4 lamp kinos...

The "mix-n-march" tubes seems more like it...

Thanks for the input, will be more picky about tubes next time around...

oscar jimenez · June 23, 2005

This is quite weird, I own two 4ft 4 bank kno's and besides that 3500k issue, never have experienced such problem, if the tubes were kino, that's certainly strange.